Following the dramatic finale of Season 3, Oxford’s finest are picking up the pieces of their personal and professional lives. DC Endeavour Morse (Shaun Evans) awaits the result of his Sergeant’s Exam, while DI Fred Thursday (Roger Allam) and his wife Win struggle to cope with their children flying the nest; Sam gone to the Army and the traumatized Joan, gone off to who knows where? But there are even greater challenges still to face. The Summer of Love is emerging, and the Oxford City Police finds itself caught on the frontier of the future—computers, pop music, National Health, nuclear power—as the struggle between old and new plays out on the battleground of Oxford. But with every force for progress, there is one with ill intention; and Endeavour, Thursday, and their colleagues are plunged into their most perilous, baffling, and terrifying cases to date.