Years ago, when he was a child, Maurice refused to go on the Underground because he was scared of all the dead people. His father had asked him a few questions and glanced at his bedside table, and explained that the Underground wasn’t the same thing as the Underworld that he’d been reading about in his Myths & Legends of the Ancient Greeks book, which his aunt Jane had given him for his birthday. There were no dead people, three-headed dogs or sinister boatmen down there, his father promised him, just crowded platforms, unreliable trains, people in scruffy old coats who talked to themselves, a really quite small proportion of homicidal lunatics and a rather unsavoury smell. He’d been reassured (though he’d secretly quite fancied seeing a dog with three heads) and withdrawn his objection. Nevertheless, even now, there was something about it—

Especially at night, in the uneasy lull between the rush hour and the last junkies-drunks-and-theatre-goers specials, when the platforms are quiet and deserted and nobody can hear you scream; when the tiled corridors echo footsteps, and the trains, when they finally arrive, come bursting out of the darkness like dragons. Since he’d had to work late at the office recently – not because there was work to be done, but because the firm was rationalising, so everyone was sticking to their desks like limpets after nominal going-home time, to show how indispensable they were – he’d had more than his comfortable ration of nocturnal Tube travel recently, and it was starting to get on his nerves.

There were three people in the compartment when he got in, all women. There was an elderly bag lady in a thick wool coat, muttering to herself and knitting what looked like a sock. Opposite her was an elegant middle-aged businesswoman, with dark hair and glasses. She was knitting, too; that seemed a little out of character, but it was just starting to get fashionable again, or so his mother had told him. In the far corner there was a rather nice-looking girl, and she was knitting, which suggested his mother had been right about something, for once. In any event, they seemed harmless enough. He chose a seat in the middle of the carriage, sat down, opened his book and raised it in front of him, like a shield.

The windows were black, of course, so there was no visible world outside; all he could see in the one next to him was the reflection of the pretty girl, and it didn’t do to dwell on pretty girls who might look up and figure out what you were doing. Instead, he looked up at the advertising boards. One caught his attention, as it had been designed to do—

WHERE IS THEO BERNSTEIN?

That was all: white letters on a black background. For a moment he allowed himself to wonder who Theo Bernstein was and what he was selling. Then he realised he’d been ensnared by evil capitalists and looked away. Out of the corner of his eye, he saw the elegant businesswoman bite through a strand of wool with her teeth. It was an incongruously savage act – though perfectly reasonable, when he thought about it; after all, you aren’t allowed to have sharp things on you in a public place. Teeth, however, are the oldest and most basic weapons of all.

The train had slowed down to the point where, with no view through the window, it was impossible to tell if it was moving or standing still. He yawned. He’d had enough of this journey. He was in the kind of limbo, between the culmination of one sequence of events and the start of another, that you get in restaurants after you’ve finished eating, before they bring the bill. He looked around for something (other than the pretty girl) to graze his mind on. Not much of that kind of thing in a Tube compartment. Further down the carriage, he saw four more black advert boards with white lettering. The Theo Bernstein people were clearly determined to get their message across. He shuffled in his seat to get comfy, and tried to read his book. But that was no good. It was a self-help thing She’d given him to read, shortly before She’d stormed out of his life, slamming the door on the sunlight, and he really couldn’t be bothered. Coping with Rejection, snickered the chapter heading. Yeah, right.

“All that time, he never realised.”

The old woman had spoken. He winced. He hoped she wasn’t going to make a nuisance of herself.

“He never realised,” she repeated, “that she was carrying on with his worst enemy, behind his back.”

Oh God, he thought, and glanced up to see how many stops there were still to go. But, since he hadn’t been keeping track, he wasn’t entirely sure where he was. Could be anywhere.

“Right under his nose,” said the elegant woman.

She hadn’t looked up from her knitting. Maurice peered at her round the cover of his book. Odd, he thought.

“He’ll find out quite soon,” said the old woman. “He’ll be heartbroken.”

Actually, she didn’t sound particularly batty. If anything, she sounded like a Radio 4 anchor. So, come to think of it, did the elegant woman, who now said, “That and losing his job.”

Presumably, then, they knew each other. Then why were they sitting half a compartment apart?

“Of course,” said the girl, “quite soon that’ll be the least of his worries.”

Um, he thought. So all three of them knew each other. The girl, who sounded like a trainee Radio 4 anchor, soon to make her debut seguing from the shipping forecast into Farming Today in the wee small hours, took a ball of green wool out of her pocket and, apparently without aiming, threw it across the compartment. The elegant woman caught it one-handed. She hadn’t even looked up.

“Getting the new job will cheer him up,” the old woman said.

The elegant woman threw her a ball of red wool.

“But not for long,” the girl said. “He won’t be able to enjoy it, because of the weird stuff.”

The elegant woman frowned. “He’ll find it suits him better.”

“Up to a point,” said the girl. “But then he’ll make a big mistake.”

“He always did have such a vivid imagination,” sighed the old woman. “Even when he was a wee tot, bless him. Could I have the yellow, please, dear?” She raised her hand and a yellow ball sailed through the air, straight into her fingers. “Now I’m not quite sure what comes after that.”

Something odd, really odd, about this conversation. “His friend,” prompted the girl.

“What, the one who—?”

“His other friend,” said the elegant woman. “Steve, in the army.”

Maurice twitched. He had a friend called Steve, in the army. Of course, his Steve was a girl – Stephanie, at one time the boss barracuda in the Kandahar motor pool.

“That’s right, silly of me. His friend Steve. She won’t half give him a surprise.”

A theory, born of desperation, floated into his mind: a variant on the old kissogram theme, he postulated, in which your friends hire paid performers to weird you out of your skull, while filming the whole thing on covert CCTV. Except he didn’t have any friends with that sort of imagination or money, or who cared enough about him to go to so much trouble. In which case, it was just a coincidence. After all, lots of women called Stephanie get called Steve.

“He always did like her more than he cared to admit to himself,” the old lady went on; and he thought, Coincidence? Seriously?

“Remind me,” said the elegant woman. “What’s the name of that boy they were both at school with? The one she eventually marries.”

“You mean the one who became rich and famous? George something, wasn’t it?”

George. Right, he thought, that’s quite enough of that. He was just about to stand up, when he realised what the odd thing – the other odd thing – was. They were talking about the future—

“It doesn’t last, though,” the girl said.

“Now then.” The elegant woman sounded reproachful. “We’re getting ahead of ourselves. If we’re not careful, we’ll drop a stitch.”

He wasn’t a brave man, and the thought of accosting three strange women in a public place would normally shrivel him down to the size of a small walnut. This, though, was different. He had no idea what was happening, he definitely didn’t want to know, but he knew, with a kind of fatal clarity, that he was going to have to ask. He cleared his throat and said, “Excuse me.”

They didn’t seem to have heard him. “After he’s killed the snake,” the elegant woman said.

“Excuse me.”

The old lady frowned. “Oh, it’s a snake, is it? Must’ve got in a bit of a tangle.”

“Definitely a snake,” the elegant woman said. “Well, sort of a snake. Anyhow, after he’s done that—”

“I’m talking to you.” Maybe, but they weren’t hearing him.

“Is that before or after he gets fired from – what’s the name of the firm?” the girl was asking.

“Overthwart and Headlong, dear. You remember. Before, definitely,” the old lady said authoritatively. “Then the snake.” She paused. “I think.”

Overthwart & Headlong, whose offices he’d just come from. Fired? Oh shit . . .

“Damn. I’ll have to unpick.”

The old lady smiled sympathetically. “Some of these plait-stitch patterns can be a bit confusing,” she said. “It was so much simpler in the old days, when everybody was either plain or purl.”

There was a gentle but perceptible jolt. The train was moving. “Ooh,” the girl said, “we’re nearly there; we’d better get a move on. Where had we got to?”

“The snake,” said the elegant woman, as she polished her glasses on her sleeve.

“What about the choice?” the old woman said.

“Oh hell.” The young woman pulled a savage face. “Now I’m going to have to unpick three whole rows.”

“Excuse me,” Maurice said weakly.

“Are you sure the choice comes before the snake?” the elegant woman said. “I thought the choice came in between the bottle and healing the wounded king.”

The what? He opened his mouth, trying to say Excuse me, but no sound emerged.

“She’s right,” the old woman said. “Stupid of me. I’ve got the pattern upside down.”

The girl shot her a furious glare. “So it’s the snake, then the bottle, then the choice and then the king and presumably the goblins after that. Or is it the choice and then the bottle?”

“EXCUSE ME.” He hadn’t intended to roar, but it was the only way he could get his mouth to work. He roared so loud they could probably hear him in the street above. The women took no notice.

“Check,” the elegant woman said. She glanced at the window, which was still completely black. “Well,” she went on, “we cut that pretty fine, but we got there in the end.”

The girl was stuffing her needles and wool into her bag. “Talking of which,” she said.

“Sorry, dear. Oh yes, of course.” The old woman nodded eagerly. “The end. How will it end?”

“Badly,” said the elegant woman.

The girl clicked her tongue. “Well, of course badly,” she said impatiently. “But how exactly? We can’t just say badly and leave it at that; they’ll want details. Like, for instance, what’s the cause of death?”

The old woman frowned. “Entropy?”

“His death.” The girl sighed. “Precisely when and how does he—?”

With a strangled cry, Maurice jumped to his feet, grabbed at the elegant woman (who happened to be nearest) and felt his fingers close on the lapel of her jacket. On and through.

The sound they made was like those fireworks that scream as they shoot up into the air; appropriately enough, because that, as far as Maurice could tell in the circumstances, was what the three women did. It was as though they’d all been simultaneously sucked into the thin nozzle of an invisible, exceptionally powerful vacuum cleaner; they sort of compressed from three dimensions to two, into straight vertical lines, just before vanishing with a sudden bright blue flare and a distant roll of thunder. At which point, the train stopped, the doors slid open and three Japanese tourists and a bald, fat man in a raincoat got in. Through the window, Maurice could see a sign saying Piccadilly Circus. The automated voice said, “Mind the gap”, the doors closed and the train gently moved forward.

Maurice’s eyes were very wide. Piccadilly Circus was where he’d got on. He fumbled with the sleeve on his left arm and dragged his shirt cuff off his watch. He’d left the office at 7.45. It was now three minutes to eight—

Oh hell, he thought. Here we go again.