"Two serial killers have been getting away with murder for years. For them, it's a well-paid hobby while they bide their time. It's about to stop when everything slots into place for them to leap to the next level. Payback for the people who killed their parents. Lambeth Group investigator, Gavin Shawlens, is on their trail. But all is not as it seems and he is pushed way out of his depth when the killers turn on his family. Gavin's Lambeth Group partner, Zoe Tampsin, is cut off from him and fighting her own battle to stay alive."