Kaylee hummed quietly to herself, something she’d heard somewhere, and it stuck in her mind. She didn’t know what it was, didn’t care. It was pretty and it made her feel happy.

“Are you ever going to do what you’re told?” Simon said from the doorway to the engine room.

The young mechanic turned to smile at him. “Are you going to tell me off?” she asked. “Don’t. I just wanted … I needed to make sure she was okay. I mean, the Cap’n don't know how to do anything ‘cept fix a catalyser, and the only one anywhere near decent in the rest of this crew is Hank, and he’s a pilot, not an engineer.”

“That doesn’t mean you should be here.” He stepped across the threshold. “I told you to rest. If you wanted to come here you should have asked me.” His voice was gentle, but his meaning was clear.

Kaylee bridled a little. “So I gotta ask every time I want to do something?”

“Not every time, no. Just when you want to do something stupid like go on board a leaky boat and fix an engine that nearly kills you,” Simon said, inadvertently letting his worry show as anger.

“I didn’t know there was a radiation leak!” Kaylee protested. “Anyway, Jayne got me out of there.”

“Only because he knocked me out first,” Simon said.

“Oh.” Kaylee lifted her eyebrows in surprise. “Nobody told me about that.”

“He hit me, and with more force than was entirely necessary,” Simon explained, touching the lump on the back of his skull where it was still tender.

“You were going to charge to my rescue?” Kaylee asked.

“Of course.” He looked at her. “Did you think I wouldn’t?”

“I …” She looked down at the engine part in her hand. “No-one said. I thought the Cap’n -”

“It didn’t get that far,” Simon interrupted. “Mal was about to give orders, I said I was going, then Jayne hit me. Next thing anyone knew he was out in the airlock and fighting his way to you.”

Kaylee smiled sweetly. “I’ll have to thank him.”

“You already did,” Simon pointed out. “Twice.”

“He saved my life, Simon. You should be ha