The 'white heat' of technology takes centre stage in the first film, as Lovelace College is taken over by a team of research scientists who are developing a 'thinking' machine to equal and even outstrip the capabilities of man's own mind. As a Russian academic prepares to do battle with the Joint Computing Nexus (JCN or Jason for short) in a game of chess, the Cold War is played out on a chequered field and Endeavour and Thursday are plunged into their most perilous, baffling and darkly terrifying case to date. Throwing himself into his work to mask the heartache of Joan's departure, Endeavour is quickly consumed by his duties when one of the research team is found drowned near Magdalen Bridge. Assuming it to be a sleeping on first inspection, the circumstances become more suspicious when two more victims are also found drowned nearby in East Cowley Baths. Is there more to the passings than meets the eye?

The so called 'permissive society' comes under the spotlight as Endeavour is tasked with protecting conservative social activist, Joy Pettybon, after she receives a passing threat while visiting Oxford to promote her 'Keep Britain Decent' campaign. Also staying near Oxford and recording their new album are a band called The Wildwood and their manager Ralph Spender, who is desperate to maintain their squeaky-clean image in the media spotlight. However, their harmony is disrupted when the body of local brickie, Barry Finch, is discovered in the middle of Oxford and it transpires that Finch was working at Maplewick Hall, where they band are staying, before he died. Delving into the social revolution of the time, Endeavour finds himself caught in the crossfire of bitter liberalising forces and deep reactionary conservatism both fighting for the consciences of the British people in 1967. And in this collision of two worlds, Endeavour must explore all avenues before more huggings occur.

Whispers that Cowley General contains a cursed ward - and a seemingly innocuous passing - set off a chain of events that lead Endeavour to investigate the dark depths of the hospital. While there, he is forced to confront his own ghosts as he discovers a chilling secret.

When a body is found in a marshland outside of Oxford, everyone assumes they are the remains of an Oxford botanist who mysteriously disappeared near the site five years earlier.