It happened by degrees. It was a gradual thing, so slow that it was hardly noticeable at all.

It started, Napoleon later surmised, with the reflective surfaces. He wasn't sure how, or where, or when, but at some point he had stopped checking them. No longer did he look at small mirrors and polished teapots and chrome surfaces to glimpse the Russian agent's movements behind his back. No more tilting mirrors to odd angles that were perfect for surveillance. No more quick, paranoid glances with finely-tuned peripheral vision. No; somewhere along the way, those had stopped.

The bugs and the trackers, of course, never had. But they were different now. No longer placed out of suspicion, but rather for the sole purpose of ensuring his partner's safety (just like the Russian trackers still safely nestled into his own boots).

Other things were different, too - subtle changes that the American agent hadn't even recognized before. The absence of the tension he had once felt while in Illya's presence. The slow change of the constant banter between them - things originally meant as slights were now, oddly enough, terms of endearment - nicknames. Insults that were once meant sincerely were now said in jest ("Absolutely hated working with you, Peril.").

And on top of all this, even more telling was the slow, creeping change in Napoleon's working style. So used to working alone, the concept of reliance on a partner had been an uncomfortable one for the American spy. And yet somehow, said reliance had crept into his working style even without his permission. He grew used to the imposing presence at his back as he deftly picked lock after lock. He no longer strained to hear approaching footsteps as well as the click of the lock; he knew without checking that Illya was keeping a lookout. In a firefight, he became accustomed to the feel of someone else's back against his, rather than the cold hard side of a wall. And when he ran between two points of shelter, he didn't have to tell the Russian agent to cover him; it was already a given.

Yes - in hindsight, all the signs were there. Napoleon could never say when exactly it happened, but it had happened nonetheless. Napoleon Solo trusted Illya Kuryakin. The American agent knew this perfectly well. But for Illya, apparently, it had been a bit of a surprise.

...

Bucket of ice in hand, Illya Kuryakin strode down the hallway of the hotel he and Solo were currently staying in. He turned right, heavy footsteps muffled on the soft red carpet, and headed towards his room, where he and Solo had been (somewhat tiredly) celebrating the successful completion of their most recent mission. Reaching the door, the Russian pushed it open and entered the room - a sprawling den of plush couches and expensive furniture, with large wooden doors to the right that opened onto the bedroom. The balcony doors at the back of the room were open partially, letting the evening breeze sweep quietly inside. At least Waverly was never stingy about their lodgings, Illya mused as he set the ice bucket on a nearby table. Swinging the room door shut behind him, he continued on into the middle of the room, and then stopped short in surprise.

Napoleon Solo was sprawled across the nearest couch, eyes closed, half-finished drink abandoned on the table. For a second, Illya wondered if something was wrong with the American agent. But the thought vanished immediately; the gentle rise and fall of the American's chest spoke clearly enough for his well-being, not to mention the fact that neither spy had been injured at all on their mission (a rare victory). And the possibility of a laced drink was ruled out immediately as well; Illya had had a glass, too. Frowning slightly, the Russian agent moved forward.

"Cowboy?" he asked, hesitantly. The note of confusion was evident in his voice. "Something wrong?" The American shifted slightly, but otherwise made no acknowledgement. Frown deepening, Illya strode to the couch and tapped his partner's shoulder. "Solo!" he said. The former thief made no move at all this time, but before Illya could do anything else, the American spoke up.

"Something the matter, Peril?" he asked calmly, eyes still closed, posture still relaxed. A small wave of relief ran through Illya at the confirmation that the American was indeed all right, but now the Russian's confusion only deepened.

"Everything's fine," Illya responded. "But... what are you doing?" he asked. This time, Solo opened one eye, watching Illya amusedly.

"It's called sleep," he informed him. "It's this strange thing that human beings need. You may have heard of it." Illya rolled his eyes as the American closed his own once more. And he laid there, perfectly relaxed, completely content, and utterly... vulnerable. It was strange, Illya thought, still frowning. To be so open to attack like that. It went against everything he - and doubtless Napoleon, too - had ever been taught about spying. You must remain alert. You must be constantly vigilant. And, above all, you must never let your guard down. And yet here was Napoleon Solo, sleeping calmly in front of a spy. Likely sensing Illya's continued attention, the American agent opened both eyes this time, curiously taking in Illya's troubled expression.

"What's wrong?" he asked. Illya paused, wondering how best to express just how defenseless the American agent was allowing himself to be. Finally, Illya just shrugged.

"I could've snapped your neck," he said bluntly. But the American only grinned. He closed his eyes and settled back into the couch, sinking deeper into its cushions. He flung one arm carelessly over the back of the couch, while the other draped limply over the side, fingers inches from the thick carpet. He was completely unprotected, and he knew it, yet still he remained entirely unconcerned. It bothered Illya. How could he be so untroubled? It's not like he didn't care for his own safety; Illya knew that Napoleon Solo was a careful man. But this... this was not careful. And it made no sense.

"Did you hear me?" Illya asked finally, perturbed. "I told you, I could snap your neck." Again, the American only smiled.

"I know," he said simply. "But you won't."

Illya was stunned into silence. The implications of those words crashed over him in one shattering epiphany that hit him like a ton of bricks. The American spy was content to be so unguarded simply because he felt he didn't need to have his guard up. He didn't need to be constantly vigilant. He didn't need to track the Russian's movements. He didn't feel uneasy, or tense, or uncertain. So yes, Illya could quite easily snap the American's neck in two. But he wouldn't. And his partner knew he wouldn't.

The truth was obvious now: Napoleon Solo trusted Illya Kuryakin.

It was weird. It was a little crazy. The idea that someone could place - had placed - their trust in Illya was an idea that was totally foreign to the Russian. This concept of trust was so different from anything he had experienced before. Amazed, Illya sank quietly into a nearby armchair and watched as his American partner slept on, vulnerable and yet perfectly at ease.

Yes, the feeling of having someone's trust was utterly strange. But, Illya realized as the night breeze blew through the balcony doors, he found that he rather liked it.