“You said Vardy thought I had nothing to be worried about,” Billy said. “I thought he was never wrong.”

“Never is,” she said, and shrugged. “Never know, though, know what I mean?”

“This is just basic precautions,” Baron said. “You should see my house. Stick around here a couple of days, while you chew stuff over. We’ll keep you in the loop. We’ve got feelers out, we know what we’re looking for. The offer’s on the table. Get back to us soon, eh?”

Billy shook his head hopelessly. “Jesus, give me a chance…”

“Think all you want,” Baron said, “but think to yourself, alright? Kath?” Collingswood lightly touched his Adam’s apple. He recoiled.

“What was…?” he said.

“Try chatting now,” she said. “For your own sake. Trust me.”

“I do not trust you.”

“Wise man.”

“Pay attention. This is my number.” Baron gave him a card.

“You don’t get mine yet,” Collingswood said. “You got to earn that sort of shit.”

“Anything worrying, anything strange,” Baron said, “or, on the other hand, when you decide you’re on board…”

“If,” Billy said.

“When you decide you’re on board, call.”

Anything strange. Billy remembered the bottled corpse. That greyed skin, those drowned eyes.

“Seriously.” He spoke quietly. “What did they do to that guy? How did they get the squid out of there?”

“Now, Mr. Harrow,” Baron said. He shook his head, friendly. “I told you. All those whys is not a helpful way of looking at things. And blimey, there’s plenty of stuff you’ve not even seen yet. How could you possibly understand what’s going on? If you even wanted to. Which, as I say, dot dot dot.

“So. Rather than trying to get to grips with things you can’t possibly, I’d just say wait. Wait and see. Because you will see. There’s more to come. Good-bye now.”

AT THE ENTRANCE TO THE FLAT, WHERE COLLINGSWOOD HAD fiddled, there were marks. Tiny scratches. A little balsa lid, flush with the wood. He flicked it with his fingernail.

Billy was hesitant to trust whatever protection it was he’d been afforded. He double-locked his door. He stared out through glass at the rooftop where that dirty bloody squirrel lay unseen. He wished it drowned in rainwater.

He hunted online but failed to find a single detail of the FSRC. Thousands of organisations of those initials, but Baron’s unit was nowhere. On his university page Billy read Vardy’s publications list. “Oedipus, Charisma and Jim Jones;” “Sayyid Qutb and the Problem of Psychological Organisation;” “The Dialectics of Waco.”

Billy drank wine in front of the television on mute, a bottled shadow-show. How often, he thought, are such offers made? A knight emerging from a wardrobe with the offer of another place but you have to come now. Was the squid out there, or destroyed? He did not trust his potential colleagues. He did not appreciate their recruitment methods.

In the television light he watched the curtains hang limply, remembering the obscene discovery in the museum basement. He did not think he was particularly exhausted. He imagined the window beyond the fabric. He woke abruptly in a panic on his sofa.

When the hell had he fallen asleep? He remembered no transition. The book he did not even remember starting to read slid from him like an inadequate blanket. It was dark. Billy realised he had heard tapping at his door.

A patter like the feet of a gecko on the other side of the wood. A nail scratching and, yes, a whisper. Billy was silent. He told himself it was some remnant dream, but it was not. It sounded again.

Billy crept to the kitchen and picked up a knife. The faint faint noise continued. He pressed his ear to the door. He unlocked it, watching his own bravery and ninja stealth, bewildered. As he pushed, Billy realised that he should be calling Baron, of course, instead of indulging this incompetent vigilantism. But momentum had him, the door was opening.

The hallway was empty.

He peered at his neighbours’ entrances. There were no evidential drafts, no slips of air to insinuate doors quickly closed. No dust dancing. Billy looked at nothing. He stood there for moments, then minutes. He leaned out like a figurehead, to see as far down those corridors as he could, keeping his feet inside his flat. Still there was nothing.

He did not sleep in his bed that night. He took his duvet to the sofa, closer to the front door, so he could hear. There were no more sounds, but he slept hardly at all.

IN THE MORNING HE ATE TOAST IN A TOO-SILENT FLAT, WITH MORE silence from outside weighing on the windows. He pulled the curtains apart enough to look at a grubby grey day, at knots of wood and leaves and blown plastic bags, at the unlikely haunt of the squirrel voyeur.

He was never one with a plethora of friends, but Billy did not often feel lonely, not like this. CN U COME OVER, he texted Leon. STUFF 2 TELL U. PLEASE. He felt he was yanking out of a trap in which Collingswood and Baron had placed him. Brave, rebellious animal. He hoped this escape was not a gnawing off of his own limb.

When Leon arrived Billy hung out from the doorframe again. “What kind of arsing around is this?” said Leon. “It’s a bloody weird night, I just had about three fights on the way here, and me such a peaceable soul. I brought your mail up. Also wine.” He held out a plastic bag. “Early though it is. What the hell’s going on? To what do I owe…? Jesus, Billy.”

“Come in.” Billy took the bag and envelopes.

“As I was saying, to what do I owe two visits in such quick succession?”

“Have a drink. You aren’t going to believe this.”

Billy sat opposite Leon and opened his mouth to tell him everything. But could not work out whether to start with the body in the jar, or the police and their strange offer. His tongue flopped over, momentarily meatlike. He swallowed. As if recovering from some dental treatment.

“You don’t understand,” he told Leon. “I never had a big bust-up with my dad, we just sort of dropped out of touch.” He was continuing a conversation from months before, he realised. “My bro I never liked. That was deliberate, dropping him. My dad, though…”

He had found his father boring, was all. He had always had the sense that the faintly aggressive man, who lived alone after Billy’s mother’s death, had found Billy the same. It had been several years since he had let contact wither.

“Do you remember Saturday morning television?” he said. He had meant to tell Leon about the man in the jar. “I remember this one time.” Showing his father some cartoon that had enthralled him, Billy had seen the bewilderment on the man’s face. The inability to empathise with his boy’s passion, or pretend to. Years later he reflected that that was the moment-and he no older than ten-Billy started to suspect that the two of them did not have much of a shot of it.

“I’ve still got that cartoon, you know,” he said. “I found it recently, streamed on some website. You want to see it?” A 1936 Harman-Ising production, he had watched it many times. The glass-jar inhabitants of an apothecary’s shelves on an adventure. It was extraordinary, and frightening.

“You know what happens,” Billy said. “Sometimes when I’m preserving something or doing something in the wet labs or whatever, I clock that I’m singing one of the songs from it. “Spirits of amo-o-o-onia…’”

“Billy.” Leon held out a hand. “What’s going on?”

Billy stopped and tried again to say what had happened. He swallowed and worked against his own mouth, as if expelling some glutinous intruder. And with a breath finally he began to speak what he had intended. What he had found in the basement. He told him what the police had offered.

Leon did not smile. “Should you be telling me this?” he said at last. Billy laughed.

“No, but, you know.”

“I mean, it’s literally impossible, what happened,” Leon said.