The phone started to ring again and he jumped, almost slipping off the end of the jetty. The cheesy ringtone bounced around inside the roof. He could see the illuminated iPhone clearly now against the opposite wall of the boat shed, lying on its side on a lip of wood just above the frozen waterline. It had a sparkly jewelled case. Lee went to the rowing boat and swung a leg over. He placed his foot on the wooden seat and tested his weight, still keeping the other foot on the jetty. The boat didn’t budge.

He swung his other leg over, climbing into the boat, but even from here the iPhone was still out of his reach. Spurred on by the thought of folded bank notes, thick in the pocket of his trackies, Lee hooked his leg over the opposite side of the boat and tentatively placed his foot on the ice. Holding on to the edge of the boat, he pressed down, risking a wet foot. The ice held strong. He stepped out of the boat and placed his other foot on the ice, listening for the telltale squeaking sound of tension and weakness. Nothing. He took a small step, and then another. It was like walking on a concrete floor.

The eaves of the wooden roof slanted down. To reach the iPhone, Lee was going to have to get down on his haunches.

As he squatted down, the light from its screen illuminated the inside of the boat shed. Lee noticed a couple of old plastic bottles and bits of rubbish poking up through the ice, then something which made him stop . . . it looked like the tip of a finger.

His heart racing, he reached out and gently squeezed it. It was cold and rubbery. Frost clung to the fingernail, which was painted a deep purple. He pulled the sleeve of his coat over his hand and rubbed at the ice around it. The light from the iPhone cast the frozen surface in a murky green, and underneath he saw a hand, reaching up to where the finger poked through the ice. What must have been an arm vanished away into the depths.

The phone stopped ringing, and was replaced by a deafening silence. And then he saw it. Directly underneath where he crouched was the face of a girl. Her milky brown swollen eyes stared at him, blankly. A clump of dark hair was fused to the ice in a tangle. A fish swam lazily past, its tail brushing against the girl’s lips, which were parted as if she were about to speak.

Lee recoiled with a yell and leapt up, his head crashing against the low roof of the boathouse. He bounced off and landed back on the ice, legs sliding away under him.

He lay for a moment, stunned. Then he heard a faint squeaking, cracking sound. Panicking, he kicked and scrabbled, trying to get up, to get as far away from the dead girl as he could, but his legs slid away under him again. This time, he plunged through the ice into the freezing water. He felt the girl’s limp arms tangling with his, her cold slimy skin against his. The more he fought, the more their limbs became intertwined. The cold was sharp, absolute. He swallowed foul water and kicked and flailed. He somehow managed to heave himself away to the edge of the rowing boat. He heaved and retched, wishing that he’d reached that phone, but his thoughts of selling it were gone.

All he wanted now was to call for help.

2

Erika Foster had been waiting for half an hour in the grubby reception area of Lewisham Row Police Station. She shifted uncomfortably on a green plastic chair, one of a row bolted to the floor. The seats were faded and shiny, polished by years of anxious, guilty arses. Through a large window overlooking the car park, the ring road, a grey office tower, and the sprawling shopping centre fought a battle for visibility in the blizzard. A trail of melted slush ran diagonally from the main entrance to the front desk where the desk sergeant sat, regarding his computer with bleary eyes. He had a large jowly face and was absently picking at his teeth, pulling out a finger to inspect the findings before popping it back in his mouth.

‘Guvnor shouldn’t be long,’ he said.

His eyes moved down Erika’s body, taking in her thin frame, clad in faded blue jeans, woollen jumper, and a purple bomber jacket. His gaze came to rest on the small suitcase on wheels at her feet. She glared back at him, and they both looked away. The wall beside her was a mess of public information posters. don’t be a victim of crime! declared one, which Erika thought was a pretty stupid thing to put up in the reception area of an outer London nick.

A door beside the front desk buzzed and Chief Superintendent Marsh came into the reception area. His close-cropped hair had greyed in the years since Erika had last seen him, but despite his exhausted face, he was still handsome. Erika got up and shook his hand.

‘DCI Foster, sorry to keep you. Was your flight okay?’ he said, taking in what she was wearing.

‘Delayed, sir . . . Hence the civvies,’ she replied apologetically.

‘This bloody snow couldn’t come at a worse time,’ said Marsh, adding: ‘Desk Sergeant Woolf, this is DCI Foster; she’s joining us from Manchester. I’ll need you to assign her a car asap . . .’