It's spring 1972 and Endeavour's return to Castle Gate coincides with another homecoming, that of the celebrated Oxford Concert Orchestra, led by illustrious composer Sir Alexander Lermontov. A gruesome discovery in a College garden leads Endeavour and Thursday to the orchestra's door, and when a second tragedy hits, they uncover a web of secrets.
Meanwhile, grisly London business turns up in Oxford and a criminal from the Smoke is brutally murdered in a derelict warehouse. As the mystery unfolds, Endeavour and Thursday realise there are some unsettling ties to a case the pair had hoped was long since behind them.