In the near future, on a decimated Earth, Paul and his twin sons face terror at night when ferocious creatures awaken. When Paul is nearly killed, the boys come up with a plan for survival, using everything their father taught them to keep him alive.

DI Walter Gambon is a self-styled “Yoda of the force”, whose workload suddenly increases when he’s handed the cases of an officer who committed suicide by throwing himself under a Tube train. Or was he pushed? Gambon must work out whether his former colleague was murdered, while tracking down another officer who has gone so far undercover that nobody knows where he (or she) is.