The series starred Marius Goring as Dr. (later Professor) John Hardy, a forensic pathologist based in Warwickshire working for the Home Office.

It was essentially a police procedural drama, with Hardy bringing his forensic knowledge to solve various cases.

He was sometimes assisted in his work by his wife Jo, a GP, played by Ann Morrish; the cases he investigated were usually in conjunction with detectives Fleming (Victor Winding) and Ashe (Michael Farnsworth) of the Warwickshire police.

Hardy was now a widower living in Oxford; the only other regulars in this final batch of shows were his secretary Susan Bartlett (Virginia Stride) and his lab assistant Price (Jeremy Sinden).

The series was one of the first BBC dramas to be made in colour, and throughout its four series had guest appearances from (among others) John Carson, Peter Copley, Rachel Kempson, Peter Vaughan, Clive Swift, Geoffrey Palmer, Peter Barkworth, Jean Marsh, Ray Brooks, George Sewell, Anthony Valentine, Jeff Shankley, Bernard Lee, Lee Montague, Geoffrey Bayldon, Mike Pratt, Edward Fox, André Morell, Brian Blessed, Nigel Stock, Philip Madoc and Warren Clarke.