Jason was back on the roof of the trailer, thankfully in much better weather, when a familiar red sports car drew up alongside and Mark climbed out. "Thinking of adding an upstairs?"

"Just a roof that doesn't leak." Jason pointed at the door. "You can put the kettle on while I finish this."

Mark disappeared inside, and Jason continued to persuade sealant into the gap between two aluminium sheets that had formerly been filled only by less-than-waterproof moss. This trailer was almost certainly older than he was, and was starting to show it. At some point he was going to have to buy a new one, if he was to continue to have his own personal retreat out here.

He heard the sounds of coffee-making just as he simultaneously ran out of sealant and gap, and slid down the front of the trailer to meet Mark emerging with two steaming mugs of decaf.

"Chris cleared you to drive?"

"Yeah." Mark swallowed. "I'm thinking it might be the last time for a while. Results are in tomorrow morning."

"And about time." Jason took the mug and downed half of it in a single swallow. It was hot lying up there with the sun beating down, but still much preferable to the pouring rain of four days earlier. "He give you any hints?"

"No. Bennett wouldn't say a damn thing, so I'm pretty sure he found nothing wrong with my implants. And Samuels has been after me so much I'm starting to understand the way you feel about him." Mark sat on the hood of his car, staring into the mug. "I think it's something bad, Jase. I really do. I just hope there's something that they can do to help."

"If he let you drive, that sounds good," Jason suggested.

"I thought that. Like at least they can predict it."

"Maybe you're better?"

"No." He still didn't look up. "I know I can still pass all the coordination tests - but it's not the same. I know it's still there. It just hasn't happened while I've been doing something complicated recently."

Jason considered, and then didn't say, that maybe Mark had just lost his nerve. "Are there things that do that?"

"Still looking like MS from where I'm sitting."

"Crap." For lack of anything else meaningful to say, Jason walked round the car, scrutinising it. "Your fuel mixture's off."

"It is?"

"Exhaust pipe's the wrong colour. Much too black." Now this, he thought, was where someone who knew what they were doing would make some great analogy about teamwork and fixing things without ever having to say it explicitly. He was pretty darn sure Mark had come out here because he wanted to talk - he never came to the trailer, although he often came to the track - but that was about as far as his insight went. The right thing to say wasn't springing magically to mind.

"Can you fix it?"

Jason grinned. "I can fix anything, given the right tools." Now that definitely hadn't been the right thing to say. Mark stiffened visibly, and Jason didn't dare skirt round the subject any more.

"Look, I don't know what Chris is going to say. But if it is MS, then maybe you're in remission right now. And it could explain what they were playing at Wednesday: Ivanov as devil's advocate, seeing what it would take for you to fly against medical advice. They can test for when it's flaring up, can't they? You could still be active most of the time. That doesn't make you so very different from me. Not perfect, but a damn sight better than the alternatives."

Mark stared. "You know about MS?"

"I'd be a fool not to look it up, wouldn't I?"

"If...if it was that, would you fly with me?"

"Yes." Jason grabbed his commander's shoulder, twisting him round to look him directly in the face. "I get the migraines from hell, Princess feels lousy once a month, Tiny's far from the finest physical specimen you'll ever see and Keyop still hasn't got that stutter under control. If you're joining the ranks of the not-quite-perfect, then it's a damn shame, but provided we all know where your limits are, I can't see a problem. If you're fit to fly, we're not going to hold some medical label against you."

Mark drew a shaky breath. "God, I feel like an idiot. I guess I owe Colonel Ivanov an apology."

"I think he owes you one, winding you up like that. You'll be fine once Chris tells you what's going on." Jason reached through the open window of the car and popped the hood. "But for now, why don't we fix your car?"

"I thought you needed the right tools?"

"I think I can make do with a second pair of hands." As Mark stood up, Jason lifted the hood and surveyed the engine inside. "What have you been doing in here - growing potatoes? This thing is a filthy mess!"

Mark laughed, and joined him. "All cars look like this under the hood."

"They so do not. Does your plane's engine look like this?"

"Of course not."

"Well, then." Jason went to the trunk of his own car and returned with a handful of tools and an oily rag. "As penance for cruelty to a perfectly good car, you can start by cleaning off that hose connection there. Unless you really want all that crud in your engine when I start disconnecting things. I'll be underneath, so try not to drop it all on me."

"Jase?"

"Yeah?"

"Thanks."

He just barely stopped himself from commenting that he hadn't fixed it, yet.