“Hand it in to the evidence room, quick, before you find a way to bollix it up. Then go home. Get some sleep. You’ll need your wits about you for IA on Monday.” He jammed his reading glasses onto his nose and bent his head over the statement sheet again. We were done.

I said, “Sir, there’s something else you should know.”

“Oh, Jesus. If there’s any more fucking shite to do with this mess, I don’t want to hear it.”

“Nothing like that, sir. When this case is wound up, I’ll be putting in my papers.”

That brought O’Kelly’s head up. “Why?” he asked, after a moment.

“I think it’s time for a change.”

Those sharp eyes poked at me. He said, “You don’t have your thirty. You’ll get no pension till you’re sixty years of age.”

“I know, sir.”

“What’ll you do instead?”

“I don’t know yet.”

He watched me, tapping his pen on the page in front of him. “I put you back on the pitch too early. I thought you were fighting fit again. Could’ve sworn you were only dying to get off the bench.”

There was something in his voice that could have been concern, or maybe even compassion. I said, “I was.”

“I should’ve spotted that you weren’t ready. Now this mess is after shaking your nerve. That’s all it is. A few good nights’ kip, a few pints with the lads, you’ll be grand.”

“It’s not that simple, sir.”

“Why not? You won’t be spending the next few years sharing a desk with Curran, if that’s what you’re worried about. This was my mistake. I’ll say that to the brass. I don’t want you booted onto desk duty, any more than you do; leave me stuck with that shower of eejits out there.” O’Kelly jerked his head towards the squad room. “I won’t see you shafted. You’ll take a bollocking, you’ll lose a few days’ holidays—sure, you’ve plenty saved up anyway, am I right?—and everything’ll be back to normal.”

“Thank you, sir,” I said. “I appreciate that. But I’ve got no problem taking whatever’s coming my way. You’re right: I should have caught this.”

“Is that it? You’re sulking because you missed a trick? For Christ’s sake, man, we’ve all done it. So you’ll get some slagging from the lads—Detective Perfect hitting a banana skin and going arse over tip, they’d want to be saints to turn down a chance like this. You’ll survive. Get a grip on yourself and don’t be giving me the big farewell speech.”

It wasn’t just that I had tainted everything I would ever touch—if this came out, then no solve with my name on it would be safe. It wasn’t just that I knew, somewhere deeper than logic, that I was going to lose the next case, and the next, and the one after that. It was that I was dangerous. Stepping over the line had come so easily, once there was no other way; so naturally. You can tell yourself as much as you want It was only this once, it’ll never happen again, this was different. There will always be another once-off, another special case that needs just one little step further. All it takes is that first tiny hole in the levee, so tiny it does no harm to anything. The water will find it. It will nose into the crack, pushing, eroding, mindless and ceaseless, until the levee you built collapses to dust and the whole sea comes roaring over you. The only chance to stop that is at the beginning.