Of course, there was a physical reason for her frame of mind, too. Her body craved action, something to focus the pent-up tension, some target to hit out at. Her old shotokan master in Warley had taught her to recognize the feeling and use it. Very soon, she would have to find time to visit her new dojo in Sheffield to get that release, or the dark well of anger would boil over and the wrong target would be in the way.

For Fry, each time she found herself back with Maggie Crew in that soulless apartment now it was like leaving the light to enter a tunnel. She recalled the tunnel on the High Peak Trail, with its dripping water and landslides of rock barely held back by the wooden roof. But she had been with Ben Cooper then, and that made a difference.

Gradually, she felt her normal equilibrium coming back, and she turned the wheel towards Edendale. Her flat in Grosvenor Avenue was depressing enough, but in a tangible sort of way. It was simply dismal and uncomfortable, not laden with painful emotions. That was what she had liked about the place when she had rented it – it held no memories, no associations, not even any significant possessions from her old life. She had thrown them all away, given them to charity shops or dumped them in recycling bins – books, clothes, the lot. So the flat was empty of feeling. A cold kind of comfort.

Fry waited outside the flat until she was sure that the mood had gone. But even then, when she got inside and stared with glad contempt at the filthy walls, there was a niggle at the back of her mind, a lingering suspicion that she had brought something of Maggie Crew with her into the room. She cursed. She had learned to recognize emotional entanglement the moment it began to infect her. The first twinge of it indicated a lowering of her defences, a weakness in her immune system that had to be tackled. A course of antibiotics was what she needed, a period of isolation, perhaps.

She looked at her diary. She had made an appointment with Maggie Crew for Friday. She would phone to cancel it in the morning. She took out her pen and put a thick, black line through the date. She immediately felt better.