Zenana

December 1970, and Lady Matilda's College is tearing itself apart over a referendum on whether to go co-educational. The internal war becomes a police matter when one of the female students is found dead on the towpath, and the latest in a grim run of towpath killings. Thursday arrests Carl Sturgis on thin evidence, and when Sturgis is released, Morse and Thursday have a falling out in front of Strange and DeBryn that neither of them will forget in a hurry.

Morse, meanwhile, has started to see the pattern underneath all of Oxford's recent "freak accidents", a run of misfortunes Dorothea Frazil has been quietly counting. When Chief Superintendent Bright's wife is fatally electrocuted, the pattern snaps into focus: someone is buying out people's life insurance policies and then killing off the insured. Strange helps Morse chase the theory, and they end up at a house occupied by Sturgis, where they find Jenny Tate held prisoner.

The trail leads back to Venice and the opera house where Morse first met Violetta. There the full scope of the conspiracy opens up, and Morse discovers he has been a puppet in Ludo's plan all along, his own relationship a piece of the machinery.

Russell Lewis wrote it, Kate Saxon directed. Shaun Evans is DS Endeavour Morse, Roger Allam is DCI Fred Thursday, Sean Rigby is DS Jim Strange, James Bradshaw is Dr Max DeBryn, and Sam Ferriday is Carl Sturgis. Marianne Oldham plays Magdalena Byrne, Lucy Black is Juliet Baring, Naomi Yang is Nancy, Flora London is Bridget Mulcahy, and Don Gallagher is the Coroner.

The viatical fraud is the sort of cold, money-driven scheme the show loves to expose, and the episode explains it without ever slowing down. The Venice scenes close the loop on Morse's affair with Violetta, and the revelation that he has been a piece in Ludo's plan lands with real cruelty.

A localised mystery that blossoms into a conspiracy about trust, money and personal betrayal, and it lands hard.