‘Why didn’t you tell me sooner!’ Tanika shouted at Becks in the passenger seat of her police car as they bombed up the A404 towards Marlow, the sirens wailing and blue lights flashing.

‘Judith said I couldn’t!’ Becks said. ‘She told me I had to wait at the station, make sure you didn’t leave, and then, when Suzie rang me, I had to tell you the killer had arrived at her house and was about to shoot her.’

‘But I should have been there to intercept him!’

‘She said she couldn’t risk you scaring the killer off. She had to do it on her own.’

‘She can’t deal with a serial killer on her own!’ Tanika said as she spun the wheel, a wall of spray shooting up from the road as she took the roundabout to Marlow at speed. Becks held onto the passenger handle, petrified, but for once wishing the vehicle she was in could go faster. They were still minutes away from Judith’s house.

As for Judith, it felt as though time had stopped for her as she sat in her chair, waiting. For seconds? Minutes? She couldn’t tell.

And then she felt a presence enter the room behind her.

There was the drip, drip, drip of water falling to the parquet. This was it.

It was time to make her play.

‘Hello, Danny,’ she said.

Judith turned in her chair and saw Danny Curtis standing across the room drenched from head to foot and wearing a grey poncho-style raincoat. He’d pulled the hood back and was looking at Judith, his eyes as wild as his hair.

‘I said, hello, Danny,’ Judith said, trying to make a connection with the man. But Danny Curtis wasn’t listening. He was breathing too heavily, staring at Judith too intently.

In his hand he was holding a Luger pistol.

Only a hundred yards away, on the other side of the Thames, Suzie stood in a panic of indecision among the dripping fronds of a weeping willow, hopping from one foot to the other to stay warm as she tried to see through the driving rain towards Judith’s house.

Earlier that evening, Judith had phoned her and said that a man was going to break into her house that night. What was more, she believed the man would very possibly make his approach along the Thames in a canoe. It was his modus operandi, she’d said, which was why she wanted Suzie hidden on the other side of the river, and a little way downstream, so she could spot him as soon as possible. Just as she wanted Becks outside Maidenhead police station, ready to run in and get Tanika or some other officer the moment Suzie phoned through and told her that the man had appeared.