Ghost Computer - The Coventry Ghosts, #3

Life goes on-such as it is-for the ghosts and humans of the Wired Monk. The entity known as Piovra is becoming increasingly hard to handle, despite all the training that is being done to harness its energy. Sara the kitten ghost is pleased with how well her friend Mirela has come along with her own training. Together, she feels they are an unbeatable pair. When the CIA asks to see Sara and another ghost for a mission, the feline immediately thinks of Mirela.
Jason Jones is, unfortunately, still in the wind, having escaped his booby-trapped laboratory. There is no doubt he is continuing with his demented experiments, which includes harvesting living human brains to feed to his computer. Unknown to them, though, Jason has taken his experiments a step further, creating an almost human-like AI that calls itself Abigail. Leanne's ghost-boyfriend Robin is beginning to feel neglected, as Leanne has a tendency to be mercurial at the best of times.
The vulnerable Robin, also a teenager, enters into a relationship which could prove fatal to them all. Meanwhile, Sara and Mirela have to track down the mad scientist and derail his plans before he can unleash his true craziness on the world.