Shaun Evans and Roger Allam return as DC Endeavour Morse and DI Fred Thursday in a quartet of mysteries, each unique and breathtaking in complexity. As both men struggle to find their bearings amidst the rapidly changing climate of 1967, these four cases test their partnership in unexpected ways, as Colin Dexter's iconic detective is pushed to new extremes in his unrivaled commitment to truth and justice.

As the mutual respect of Morse and Thursday grows, so do their investigative skills -- which they'll need for a fresh set of tough-to-crack cases, including one that traces back to a disappearance five years ago.

As 1968 dawns, Endeavour's recent promotion leads him to reluctantly mentor new recruit Fancy, while Thursday is beginning to think about life after the police. But in Oxford, crime never sleeps, and the team continues to be challenged by intriguing cases of murder, greed, and deception. When 1968 comes to a close, will things at Cowley Police Station ever be the same again?

It's 1969, and things have taken a darker turn for the old Cowley team. With Endeavour, Thursday, and the gang now scattered across Oxfordshire, it takes a series of brutal crimes - including the death of a young schoolgirl, a fatal act of sabotage, a deadly campaign of gossip and rumor in a picturesque village and a murder at the Bodleian Library - to reunite them. Now joined by former adversary DCI Ronnie Box and his sidekick DS Alan Jago, the gang must battle crime and corruption to finally solve their greatest challenge - the truth behind George Fancy's death.

Endeavour and his colleagues are entering a new decade and era of change. Opening on New Year's Eve 1969, normal order has been resumed and the team reunited at Castle Gate CID, with Chief Superintendent Bright back in charge. However, the events of the past year have left their mark. Old friendships will be challenged, and new relationships will blossom.