AN: I've had the idea for this story in my head since it became clear there would be multiple Densi proposals, but wanted to wait until they were actually engaged before writing it. I'm stepping outside of my comfort zone here to include some characters from another TV show, although it's not being posted as a crossover (maybe later, depending on feedback regarding my characterization of the "couple of strangers" from those of you familiar with them) because I consider this more of a Densi/team fic with a guest appearance by Shamy (Sheldon and Amy from The Big Bang Theory). You shouldn't need to be familiar with Shamy or TBBT to enjoy this story. Just know that they are both very bright individuals, and social skills don't come easily to Sheldon, but a rather large ego does.

Special thanks to sassyzazzi and her DH, who were my TBBT and science sounding boards. And also to Max and Fern 4ever, who helped me settle on a title.

Spoilers: Anything that's aired in the US is fair game for both shows. I did take some liberties with Shamy's status post-finale, though.

Disclaimer: Nope (don't own 'em) and nada (not making any money from 'em).

"Thank god that's over," Callen said under his breath to his co-workers. Karaoke bars were always risky; if the singers were good, it was an enjoyable night out. If not, there wasn't enough alcohol to make it sufferable. He signaled the waitress over, because tonight the "entertainment" was bordering on unbearable.

"It's only the first break, Mr. Callen," Hetty reminded him, "and none of our talented group has performed yet." She raised her drink and encouraged the others, "Come now, everyone, find your courage at the bottom of your bottles if you must. Drink up, and get up there!"

"About that, what are you going to sing tonight, big guy?" the team leader turned and asked his partner. This was the first time Sam had joined the team on a night out since he returned to work after Aiden and Kamran left for school a few weeks ago. He doubted Sam would actually take the stage, but Callen felt he needed to prod him a little as he typically would have.

Sam was beginning to regret asking G to act normal around him in the hopes that the rest of the team would follow suit. Coming back to work now that the kids were at Keating, while exactly what he needed, had been more awkward than Sam had expected. He felt as if everyone was walking on eggshells around him, trying hard to avoid any topic that would remind him of Michelle or his absent children.

Time to change the subject and shine the spotlight on Kensi and Deeks, Sam thought. He figured everyone would be happy to talk about their engagement. He'd heard from the couple themselves about Kensi proposing to Deeks when they stopped by the house one day during his leave. But Sam still had a question he hadn't gotten to ask then. "So Deeks, I don't understand. You were pestering me for suggestions of places you could propose that Kensi wouldn't expect. What happened?"

"Well somebody got an unexpected proposal," Eric joked.

"Because somebody else got tired of waiting, apparently," Callen surmised.

"Okay, that's not fair. I proposed three times before Kensi asked me!" Deeks was met with more than a few disbelieving looks. He turned to his fiancée and implored, "Tell them, Kens."

"Well," she hedged, "I wouldn't say it was three times."

"What are you talking about?" Deeks put up his thumb, "First was after that case with the triplets." He extended his pointer finger, "Second was while you were in a coma. And finally," out came his middle finger, "in the courtyard at the VA hospital."

"Quite the overachiever, Mr. Deeks," Hetty said wryly.

Kensi grabbed Deeks' wrist and turned down his thumb. "I've said from day one that the conversation we had in the hallway at work, without a ring, was a pre-proposal and not an actual offer of marriage."

"The hallway at the mission? No ring? Not cool, man," Sam shook his head slowly. "No wonder you were looking for some grand gesture."

"What the hell is a pre-proposal?" Callen asked.

Nell explained, "It's kind of like testing the waters. You know, broaching the subject to find out what the other person thinks of the idea."

"Exactly," Kensi replied. "The words, 'Will you marry me?' were never spoken."

"Then what did he ask?" Eric wanted to know.

Kensi closed her eyes for a few seconds to try to recall the exact wording, "He wanted to know if I thought our lives were too crazy to get married."

"Definitely a fishing expedition," Callen agreed. "Sounds more like a trick we'd use in interrogation than a marriage proposal."

"In my defense, it was not as out of the blue as Kensi's making it sound. We had been talking about having kids," Deeks clarified.

"Whoa! In the office?" Nell was surprised she hadn't heard of this before.

"Up in the ops center across the room from you two, and then later in front of Granger, in fact," Kensi smirked at the memories.

Deeks added, "To be specific, the discussion in Granger's presence was whether to home-birth and circumcise."

Eric choked on the sip of dink he had just taken.

Kensi decided it was not the time to go down that road again. Still holding Deeks' hand, now with two fingers up looking like a peace sign, she waved them around to gain the team's attention and said, "And come on, you said it yourself, I was unconscious the 'second' time. How can that possibly be considered a valid proposal?" Kensi curled Deeks' pointer finger back to his fist, leaving just his middle finger standing.

"One might say that not only was it a legitimate proposal, but also an incredibly romantic one, princess," Deeks used his extended finger to gently turn Kensi's face toward his and give her a quick peck on the lips.

"Ooh, especially if Kensi had woken up when you asked!" Eric gushed.

Deeks hid his cringe at Eric's comment. He deliberately did not mention to their friends that he had, in fact, asked Kensi to wake up during his proposal, though Kensi now knew that detail. In Deeks' fantasy as he was mentally preparing to propose to his comatose partner, Kensi would wake up. Like Sleeping Beauty kissed by her Prince, Deeks had held out the slimmest hope that Kensi would awaken when he slipped the ring on her finger.

What Deeks hadn't told her was what happened next: his absolute thrill at Kensi moving her hand, only to be followed by the devastation of the doctor telling him that it wasn't purposeful movement, and therefore was essentially meaningless. Nor would he ever share with her the memory of Kensi jerking her hand away from him as he caressed it. Or how even though the doctor had just told him her motions weren't deliberate, Deeks had felt as if his heart had been plunged into a bucket of ice water.

When he noticed Kensi looking at him curiously, Deeks diverted her attention, "And may I just point out I put that ring on your finger despite the fact that you so rudely stayed unconscious and didn't answer me!"

"Um, hello? Coma," Kensi reminded them.

"Very true, Ms. Blye. It was unlikely that you would be able to give Mr. Deeks a response. But I don't believe that negates the proposal. He did ask, you simply did not reply."

"That was really sweet, Deeks," Nell said, tilting her glass toward him in a silent toast before taking a sip.

Sam added, "Yeah, I think that counts."

Callen was not so sure, "Wait a minute, partner. I say it doesn't. If there was no way Kensi could have answered, Deeks may as well have proposed to Monty." He caught the look of surprise from the woman in question and added, "No offense, Kens."

Kensi shrugged and took it in stride, glad that someone agreed with her.

"What about the third proposal?" Sam asked.

Kensi corrected him, "Alleged proposal. And it can't be the third if the 'first' didn't count and the 'second' is still up for debate."

"Doesn't matter, because I am not responsible for that one not ending in our betrothal." Deeks raised his eyebrows expectantly at his fiancée, and the rest of the group turned their attention back to Kensi.

She took in a fortifying breath before admitting, "I wouldn't let him finish asking."

"What?" Nell gasped.

At the same time, Hetty said, "Why on earth not?"

Callen chuckled, "I can't wait to hear this."

Kensi started to explain, "I was still at the VA, and I couldn't walk. At that point, I didn't think I ever would."

Deeks picked up the story, "So there she was, sitting in her wheelchair, and there I was, on my knee, holding out the ring – "

"No!" Eric exclaimed. "The ring and the knee?" He shook his head at the brunette, "Kensi, it doesn't get any more classically romantic than that!"

"Come on, guys! I was in a really bad headspace. I didn't want to burden Deeks if I ended up stuck in that chair forever."

Sam spoke up first, "Kensi, you wouldn't have been a hardship on Deeks, or anyone, for that matter. The man loves you, and that's never a burden."

"Partners take care of each other, Kens. You know that," Callen said.

She huffed, part frustration and part embarrassment. "Yes, I know that, when I'm level headed. But I can't claim that rational thought was part of my decision-making process that day." Seeing the serious looks on her friends' faces, Kensi added, "Besides, my idiocy is not the topic of the current conversation. We're trying to decide whether or not that act can be considered an official proposal. I say it can't, since he never actually asked."

"Proposal interruptus," Nell mused.

The group snickered and Hetty said to Kensi, "To echo Mr. Beale, 'the ring and the knee.' The intent was clear, my dear. I believe it was indeed a proposal."

"Nope, he didn't finish it, doesn't matter why. Not a proposal," Callen insisted.

"I call favoritism!" Deeks said, pointing an accusatory finger at their team leader. "Callen, you haven't sided with me once tonight."

"Kensi always was his favorite agent," Sam reminded them with a wink.

"We need an impartial opinion here," Deeks suggested as he scanned the immediate area for someone who looked sober and intelligent enough to be party to their debate. Spying a potentially suitable duo as they approached the team's table, Deeks called out, "Excuse me, you look like a very wise and handsome couple. Do you think you can help us settle an argument?"

The man, tall and slender with neatly groomed short brown hair, was wearing an ancient looking short-sleeved t-shirt with a Flash Gordon logo over a long-sleeved tee and khaki pants. The woman was several inches shorter, with long, straight brown hair and glasses. She wore a patterned blouse, unbuttoned enough to see the crew neck of another shirt beneath it. Over that was a cardigan with a completely contrasting pattern. Her stiff corduroy skirt fell to just below her knees, and the rest of her was hidden by heavy tights and what must have been very comfortable shoes. Deeks hoped they were as nerdy as they appeared.

"Well I'm not sure how you can judge our sagacity just by looking at us, but you happen to be correct." The man looked around the bar, "Unless Dr. Stephen Hawking is here, and he doesn't appear to be, I am the most intelligent person in the room." He nodded at the woman next to him, "And my intended, though her IQ is quite a few points shy of mine, is undoubtedly the second smartest."

The team glanced quickly at Nell, who smirked but remained silent. Deeks spoke instead, "Did you say that this lovely lady is your fiancée? Well that's just perfect, because we need someone to help put an end to a debate between me and my own bride-to-be. Do you have a few minutes?"

The man smiled and rubbed his hands together, "Oh, this could be fun. Our friends want to talk about wedding plans. How boring is that?"

The woman shook her head, but looked resigned to her fate. "He would rather do just about anything than help make decisions about our wedding."

"That is true. I have much more important things than color schemes, linens, and flowers to think about."

Sam got up and found two chairs for the newcomers, who sat on opposite ends of the rectangular table. The woman thanked him and said, "I'm Amy, and this is Sheldon."

"Dr. Sheldon Cooper, at your service," Sheldon clarified.

Deeks introduced everyone, leaving his "Aunt Hetty" for last, but not least.

They accepted Deeks' offer of a round of drinks, Sheldon requesting an iced tea. "Make sure it's real tea, made with actual tea bags," he emphasized to the waitress. "I once had two Long Island Iced Teas. Spoiler alert: it may have originated on Long Island, but there is no tea in it."

Hetty addressed Sheldon, "What kind of doctor are you, if I may ask?"

He said quickly, "I hold both Doctor of Philosophy and Doctor of Science degrees in physics. I also have extensive knowledge of many other subjects, including but not limited to chemistry, biology, astronomy, algebra, calculus, vexillology, engineering, history, geography, and trains."

Deeks turned to his partner and mouthed, vexillology? Kensi shrugged in response.

Amy seemed slightly chagrinned. "Sheldon, I don't think they need your entire CV."

"That wasn't my curriculum vitae," he looked around the table as he pulled out his phone. "But if you'd like to see it…"

Sam held up his hand, "No, thanks, man. I think it's clear you're more than qualified to help us out here."

"And I'm sure Amy can help too, even though she's only earned a Ph.D. in neurobiology. It's a good thing she's attractive and is also an avid vexillologist," Sheldon added.

Nell's mouth opened as if she was about to speak, but she found she was at a loss for words. Instead, she studied the physicist carefully and whispered to Eric, "Is he at all familiar to you?"

"What do you need our help with?" Amy asked, drawing everyone's attention.

Deeks explained, "Kensi and I are having a slight disagreement about how many times I proposed to her."

Sheldon said, "While often misattributed to Albert Einstein, insanity has been defined as doing the same thing over and over and expecting a different result. You might want to keep that in mind for future reference. If she rejected you the first time, you should have said your goodbyes and moved on. That's in Amy's and my relationship agreement. Ooh! I could write one for you too, if you'd like. You'll avoid all this ridiculousness in the future."

Kensi leaned closer to Deeks and reminded him quietly, "You asked him here."

Callen couldn't help himself. He leaned forward in reluctant interest and said, "Relationship agreement?"

"Why, yes. Ours is a thirty-one page binding contract that dictates the terms of our relationship."

"Like what?" Now it was Eric who was curious.

Amy replied, "For example, date night is every second Thursday of the month."

"Except when a month has five Thursdays, in which case date night is on the third Thursday instead," Sheldon supplied quickly. "Additionally, neither of us may undergo cosmetic surgery unless it is to look like a Klingon. It also outlines our plans in the event of an intelligent dog uprising. But I can't tell you the details of that."

"O-kay, then. Um, thanks for the offer, but I think Kensi and I will risk it." Deeks glanced at his partner and fiancée, who eagerly nodded her agreement. "Why don't we get back to the topic at hand, which is determining how many proposals there actually were."

"Go on, then." Sheldon nodded his encouragement. "Start with the first purported proposal."

Kensi spoke. "We were at work and we'd been talking about maybe having children, but decided it wasn't a good time for us. To have kids, that is. And as we were leaving for the day, Deeks asked me if I thought it was okay for, and I quote, 'Two people to get married.' I agreed that it was, he asked me if I was saying yes, and I very explicitly said that I was not, especially not in the hallway at work, and without a ring."

"That sounds like proof of concept," Amy said. She gaged her audience and decided to elaborate, "Evidence that an experiment, or in this case a proposal, is feasible."

Sheldon said, "For example, I just read a very interesting article about how the Chinese have successfully beamed pairs of photons linked by quantum entanglement from a single satellite to separate receiving stations here on Earth, located more than seven-hundred miles apart, essentially providing proof of concept that satellite-based quantum communication is possible. And since anyone who studies physics knows that quantum signals are effectively impervious to eavesdropping, we are now one step closer to creating unhackable communication networks over longer distances, and potentially even a secure quantum internet."

"That is thought-provoking indeed, Dr. Cooper. Perhaps you and I can discuss the applications of such a finding some other time?" Hetty suggested.

"You have an interest in quantum physics as it relates to communication?" Sheldon asked, surprised.

"Oh Dr. Cooper, I have an interest in a great many things. Would you happen to have a business card on you?"

Kensi shook her head at the turn of events. When wasn't Hetty's mind on national security? Deciding it was best to get the conversation back on track in order to divert attention away from Hetty's apparently unusual fascination with unhackable communication networks, she asked Amy for clarification. "But this proof of concept, it's not the experiment itself, right? So that wasn't a proposal?"

"Correct," Amy agreed. "A proof of concept trial is often undertaken prior to conducting the experiment, especially if it's an expensive or particularly cumbersome one, to determine if there's any possibility that the experiment can be successful. In other words, your conversation in the hallway could be considered a proof of concept for a future proposal."

"That pretty much sums up the situation," Nell confirmed.

"Well that wasn't very much fun at all," Sheldon whined.

"How about this one?" Deeks said. "Kensi was in an accident a few months later and was in a coma for some time. While she was unconscious, I asked her, using the words, 'Will you marry me?' and even put the ring on her finger. Is that a proposal?"

"That is a trick question, sir!" Sheldon responded quickly.

"How do you figure?" Sam asked.

"If Kensi was unconscious, it is reasonable to say that she was not aware of the supposed proposal. And if she was not aware of it, she could not have observed it. If no one observes an action, it is in a state of quantum superposition, meaning that unless and until it is observed, every possibility is present and equally likely. This is clearly reflected in Niels Bohr and Werner Heisenberg's Copenhagen interpretation of quantum mechanics, which posits that subatomic particles can exist in multiple states until acted upon, or in this case observed, at which time the superposition collapses into one of the possible states. Ipso facto, unless someone saw or heard this theoretical proposal, it remains in a state of superposition and simultaneously both happened and did not happen," Sheldon said, as if he had just won an argument.

Seeing the looks on her friends and colleagues' faces, Nell said, "You might recognize that as the Schrödinger's Cat thought experiment. It supposes that a cat and a vial of poison are put in a sealed box, and the poison will be released at a random time. No one knows if the cat is dead or alive until the box is opened, and in the meantime, it can be thought of as both dead and alive."

Sheldon considered the redhead, "Why yes, that's certainly a simpleton's way to look at it."

"Perhaps, but it also doesn't apply here," Nell challenged.

The man gasped, "Clearly you weren't paying attention earlier when I mentioned my two doctoral degrees in physics. Theoretical physics seeks to explain everything in the known and unknown universe; it can most certainly be applied in this situation."

"I'm sure you know more than I do about physics, Dr. Cooper, but I think you're ignoring the fact that Deeks told us he asked Kensi to marry him while she was in a coma. So while she didn't observe the proposal, he did. Therefore, it happened, and there is no state of superposition."

"Yes, but that assumes that his statement is factual, and I have no evidence of that," Sheldon countered.

Deeks offered, "The nurses found the engagement ring on Kensi's hand the next day, how's that for evidence?"

"That's fine, if all you want to do is prove the tree fell, and not that it made a sound when it did," Amy said.

"You know what?" Kensi jumped in, "I never doubted Deeks when he said he asked, so let's just say he counts as an observer of his own behavior, and that his proposal while I was in a coma was a legitimate one."

"Yes! Score one for me!" Deeks exclaimed.

"So we have one valid proposal out of two," Callen said.

"And I shall endeavor once again to be the arbiter of the legitimacy of the next 'proposal,'" Sheldon stated magnanimously before looking at Kensi and Deeks to signal that one of them should tell the tale.

Kensi did. "After my accident, I was partially paralyzed and in a wheelchair and there was no guarantee that I would walk again. One day, Deeks brought out the ring and started to propose, but I wouldn't let him finish."

"Why not? Did you think he didn't really want to marry you because you were paralyzed?" Amy asked kindly.

"I thought it would be too much of a burden on him and our relationship."

"Why that's just poppy-cock, thinking you'd be a liability because you're in a wheelchair," Sheldon was passionate in his rebuttal. "Would anyone call Dr. Stephen Hawking a burden? Of course not. And even if he was, the man's genius and contributions to the world of science have more than made up for any inconveniences and all efforts made on his behalf. While objectively, one probably can't say the same for you – "

"Sheldon, that's rude," Amy said firmly.

"No it isn't, I did say objectively. I'm sure that none of these fine people, as perfectly average as they appear to be, have made as significant a contribution to society as Stephen Hawking."

"I dare say, Mr. Cooper, you would be amazed by the accomplishments of the individuals at this table," Hetty said under her breath.

Sitting next to their operations manager, Eric beamed at the discreet praise.

"Subjectively, Mr. Deeks wouldn't have minded, I'm sure. As a typical man in love he's under the effects of copious amounts of dopamine, so he in all probability would have done anything to help and would have felt good doing it. By the way, this is just another argument in favor of a relationship agreement. Amy is obligated to keep my detached head in suspended animation should my body be ravaged by amyotrophic lateral sclerosis."

Amy translated for them, "ALS, or Lou Gehrig's Disease. The same illness Dr. Hawking suffers from."

"For when there's a cure, right?" Deeks was excited by this turn in the conversation, and elbowed Kensi knowingly.

"Or a reliable method for transferring my consciousness to a supercomputer is devised, whichever comes first."

Kensi rolled her eyes. "Can we get back to the discussion, please? I wouldn't let Deeks finish asking me to marry him. It can't be considered a proposal, right? What does the world of physics have to say about that?"

The couple looked stumped, with Sheldon periodically starting to speak and then cutting himself off before committing to any argument. Amy simply squinted her eyes and stared ahead.

Sheldon eventually spoke, "Hmmm, I believe this relates most closely to Newton's first law of motion, which states that every object persists in its state of rest or uniform motion in a straight line unless compelled to change that state by forces impressed on it."

"That's just another way of saying that Deeks would have completed his proposal if Kensi hadn't stopped him. We already know that." Nell pointed out.

Sheldon said, "Yes, I acknowledge that it doesn't help answer the question."

"This doesn't either, but it reminds me of the tongue-in-cheek fourth law of thermodynamics," Amy said.

Eric said, "Ah, Murphy's Law: Whatever can go wrong, will go wrong."

"I was thinking more of the original version: If there are two or more ways to do something, and one of those ways can result in a catastrophe, then someone will do it." Kensi heard the displeasure in the other brunette's tone.

"Yes, I get it, I screwed up. I was an idiot, and I admitted to that before you joined the party," Kensi said.

"Well, perhaps we ought to table the discussion of this alleged proposal for now and move on to the next one." Sheldon looked at Deeks expectantly.

"There were no more, at least not from me. A while later, Kensi popped the question and I accepted."

Sheldon seemed surprised, and said, "Well, that's very progressive of you both."

Deeks wasn't sure if Sheldon was commending them or not, as it was hard to judge his sincerity by his tone of voice.

"Well then I have to say your last attempt was not a proposal, since it was not fully realized. I can't publish an incomplete formula and expect my colleagues to accept it, regardless of the reason it remains unfinished," Sheldon declared with confidence.

"I concur," Amy said.

"Well, if that is all, I see that our friend Rajesh is next up to sing. Social etiquette dictates that we be there to support him," Sheldon said abruptly as he stood.

Amy agreed, "Yes. And don't forget, during the next break we need to discuss what we'll be wearing to the Renaissance Fair."

"If we must," Sheldon replied to his fiancée. To the group, he said, "Amy won't let me go as Mr. Spock on an exploratory mission any more, and I can't dress as a monk since we now engage in coitus." The pair said their quick goodbyes and made their way back to their table.

Eric and Nell gaped at one another as realization struck. "Spock at Ren Fair! That's where we know him from," he whispered to her.

"Now it all makes perfect sense," she murmured in return.

Deeks hadn't even realized the singing had started again, he'd been so involved in this very bizarre conversation. The team remained silent for a few seconds after the twosome departed, meeting each other's eyes as they tried to stifle their laughter.

"What a remarkable couple," Hetty observed, causing everyone to finally break down and laugh.

Sam, as much as he appreciated the distraction the newcomers had provided, said, "That's the last time we let Deeks pick a stranger to settle an argument."

"Hear, hear!" Callen said. "I think we all need another drink after that. Next round's on Deeks."

Deeks nodded his assent as he put his arm around Kensi and pulled her closer. "Well sugarbear, I guess that settles it. As determined by consensus and expert opinion, I did in fact legitimately propose to you once."

"I'm sorry I missed it," Kensi said earnestly.

Deeks picked up her left hand and kissed it just above the diamond ring. "It was some of my best work."

"I'm also sorry I didn't let you finish asking the last time. I should have, and I should have accepted."

"Nah, you weren't ready. It's all good, Kens. It worked out in the end, and now I have this spectacular flashbang pull ring to show for it." He removed the item from his jeans pocket, where it had taken up semi-permanent residence, much like Kensi's ring had.

"What are you going to do with that, by the way?" Callen asked.

"I haven't decided yet. What do you guys think?"

"Use it as a key ring," Callen suggested.

"You could wear it on a chain under your shirt," Nell said.

"Turn it into a zipper pull for your wetsuit," was Eric's thought.

Sam said, "Have it made into an actual ring."

"I could fashion it into a lovely tie pin," Hetty offered.

"Straighten it into a lock pick," Kensi proposed.

"Those are some…very interesting ideas. I'll have to think on them. Oh, I know! Let's bring Sheldon and Amy back and ask them," Deeks said as he made to get up.

"NO!"

AN2: I hold no degrees in physics (and the ones I did earn, Sheldon would mock as belonging to a field of "soft science"), so any mistakes when it comes to that are all Sheldon's. ;-)

I'm curious to know what people think about which of Deeks' proposals were legit…feel free to share if you're kind enough to leave a review!