"That bag is doing a great deal of clanking," the Doctor observed mildly.

"A girl's gotta make a living somehow," Scarlet replied cheekily. "Especially seeing as how I'm just handing the matrix crystal over to you."

"Scarlet, how much trouble is all this likely to land you in?"

"I've been in trouble all my life," she laughed in response.

"I'm serious. Does helping me put you in danger? Because you could come with us…"

"I'll be fine. I'm used to making my own way. Besides, three's a crowd, yes?"

The Doctor flushed and ran a finger under his collar again. "It's not like that, and even if it was, the least I can do is give you a lift…I can drop you anywhere you like, no trouble whatsoever."

"You're sweet, but I'll be fine." She spied the lane where Sentro's shop was located and made to turn, but the Doctor continued straight on. "Doctor? We want to go this way."

"Yes, we do, but not yet. First, we want to go this way."

"Why?"

"We need to pick up a bit of insurance."

"Your friend doesn't have all that much time," Scarlet reminded him.

The Doctor stopped and turned, and something in his eyes made Scarlet fall back a pace.

"I am a Time Lord, Scarlet. I have nothing but time."

"Hello, Sentro," the Doctor said with deceptive mildness.

"Guards!"

"Not coming, I'm afraid. Pressing business on the other side of this rock. Seems someone told them you were planning on leaving without paying them."

Sentro's three eyes narrowed beneath the cowl of his robe. "You do realize that this is costing your friend precious time?"

"You do realize that if anything - anything at all - happens to her…well, let's just say, they don't call me The Oncoming Storm for nothing."

Sentro looked into those ancient eyes and suddenly had the uncommon good sense to feel very much afraid.

"Now. The cure for my friend," the Doctor demanded.

"The dioptase matrix crystal," Sentro countered.

The Doctor's eyes slid to Clara's still form. "Fine." He pulled a small, ebony box from his pocket and tossed it negligently to the tentacled alien.

Sentro caught the container and rattled it, hearing a satisfying clink from within.

"The cure," the Doctor repeated, his voice all the more dangerous for its lack of volume.

Sentro barely looked up from fiddling with the catch on the box. "I'm afraid there is none," he reported maliciously.

The Doctor went utterly still. "I'm afraid there's no cure for that, either."

Sentro shrieked once, as the memory worm sank its greedy fangs into his hand the first time. After the third bite, he really didn't notice much at all.

The Doctor hurriedly crouched beside Clara, gathering her body into his arms. "Scarlet, get in here!"

She burst into the room, stepping carefully over Sentro. "Well, I can honestly say, he's never looked more pleasant."

"Never mind that right now. Do you have the box I gave you?"

"Right here," she said, producing the twin of the box the Doctor had given to Sentro from the depths of her bag.

"Good. We might need to trade that."

"What for? Did you get the cure for your friend?"

"No. He said there wasn't one."

"Calm down," Scarlet admonished. "I can count the number of times Sentro's told the truth on one hand. What bit her?"

The Doctor waved his hand at the cages full of monkey creatures. "One of those."

"Of all the times for him to take up honesty."

The Doctor looked up from his frantic examination of Clara.

"How is she?" Scarlet asked.

"Not good. Not good at all. Think. Is there any sort of medical facility here?" the Doctor asked desperately.

"You're joking."

"Scarlet, do I look even remotely like I'm joking?"

"There is one thing you could try," Scarlet replied, turning to the display tanks. "Here." She held out one of the slimy, spidery creatures. "The substance that they secrete…I've heard that it has some sort of medicinal properties. Worth a try, isn't it?"

The Doctor gently set the small animal on top of the bite marks on Clara's wrist. As he watched, the small creature oozed a bit more, then started to change color again, this time green. The swelling and mottling started to recede from Clara's hand. The Doctor took out his sonic screwdriver and scanned her. "It's working!" The little creature gave a single, rusty sounding purr, then dropped off of Clara's arm. He scanned it hurriedly. "It's not the slime…or maybe it is, but not just the slime. The creature actually seems to have absorbed the venom." It struggled weakly for a few seconds more, then went limp. "I'm so sorry, little fellow. Thank you. And thank you, Scarlet…" But she was gone, with the box containing the real crystal, of course.

Just at that moment, Clara began to stir weakly in his arms. "Hey…there you are…welcome back."

"Have I been somewhere?" Clara asked dazedly.

"You went wandering."

"Do me a favor, would you? Spare me the lecture until my head stops pounding."

The Doctor just hugged her tight against his chest and kissed the top of her head. "Come on…let's get you back to the TARDIS."

Clara sat quietly while the Doctor finished bandaging her arm. "Go on. Say it. You were right. I shouldn't have wandered off."

"It wasn't entirely your fault. And you're all right. That's all that matters," he replied quietly. "There." He dropped a light kiss on top of the bandage.

"Why d'you put up with me?" Clara wondered.

The Doctor stared off into some unimaginable distance for a long, long moment before he spoke. Clara was suddenly struck by how old his eyes were, in that boyish face.

"You make me feel young again," he finally replied, still holding her hand. "A thousand years of wandering the universe can make a body feel old…so very, very old. I was almost ready to give it all up, and let the Silence kill me, but my friends pulled me back from that particular abyss. Then I...lost…Amy and Rory, and I vowed I would never again involve myself with people, never let anyone else get close enough to me to be hurt…"

"Or hurt you," Clara murmured.

"And then I met you. And no matter how much I pushed you away, you kept coming back, with your questions, and your never-ending curiosity, and your laughter…your…humanity. When I see things through your eyes, it's like the entire universe is brand new again."

"Perhaps that's why the universe keeps bringing us together."

"Perhaps." The Doctor pulled Clara close to him and wrapped his arms about her.

"What's this?" she asked, sliding both arms around his waist.

"Just me…holding on tight…for as long as I can…"