David Cartwright, once MI5's number 2, is now old and forgetful and therefore a potential risk, but not helpless. When a stranger who claims to be his grandson arrives at his door one night, he shoots him on the spot. The real grandson, River, finds in the dead man's pockets a ticket to France, coincidentally the place where his grandfather had always "summered". River, a member of Jackson Lamb's team and his slow horses, the outlaws of the British secret service, follows this lead. For a time, Jackson Lamb had worked with the old agent and knows that the latter is responsible for many deaths by omission, sacrifice or direct liquidation. And it is Lamb who is called in to identify the lifeless body discovered in David Cartwright's home, while a bomb has gone off in a shopping mall and the slow horses of the Marsh House must act before everything escalates. Lamb will do whatever it takes to protect an agent of his in danger.
A spy novel in which the author presents an MI5 dedicated to infighting and covering up whatever might discredit it. There is brilliant prose, sardonic humor and breakneck pace. This is the fourth installment in the series about Jackson Lamb and his slow horses. The characters in the story lack principles and ideals of service to society, their family life is broken or a sham. Immoral behavior is recounted, without explicit description.