Passenger

June 1968, and the railway is the real star. The case starts as a missing person: Frances Porter, reported gone by her husband and sister, last seen meeting a lover who admits dropping her at the local station after their liaison. Morse searches an abandoned line and finds her body in a closed station. Dorothea Frazil, editor of the Oxford Mail, is quick to wonder whether this is connected to the unsolved murder, four years earlier, of a teenager whose body was found near another station. In both cases, the victim's shoes were missing.

The discovery of another body, a co-worker of Porter's, seems to confirm the pattern, but the crime-scene details nag at Morse. Something about it is off, and he is right to trust that. Meanwhile Thursday is working a lorry hijack that ended in murder, and his suspicions point at the local gangster Eddie Nero. Fancy's contact with someone handling the stolen goods suggests a different truth: another criminal waiting to take over Nero's patch.

The two investigations collide in an unexpected culprit, and the geography of the whole thing, the closed stations and the abandoned lines, earns its place in the plot.

Russell Lewis wrote it, Jim Field Smith directed. Simon Scardifield is Cedric Naughton, Shaun Evans is DS Endeavour Morse, Sean Rigby is DS Jim Strange, Jacob Fortune-Lloyd is Don Mercer, Lydea Perkins is Frances Porter, Siobhan O'Carroll is Matron, Judy Clifton is Lilian Conway, John Biggins is Burt Hobbs, Sara Vickers is Joan Thursday, and Caroline O'Neill is Win Thursday.

The missing shoes detail is the kind of quiet clue the show specialises in, and it pays off without fanfare. Fancy gets a proper share of the action here, stumbling into the middle of Thursday's hijack case, and the two investigations braid together with more elegance than the chaos around them suggests.

It is always satisfying when a town's bones, its railways in this case, help crack the mystery. This one lets the tracks do the talking.