Endeavour

Following the murder of Andrew Lewis, Detective Sergeant Morse informs DCI Fred Thursday in 1972 that Lewis' cousin, Robbie, a young police cadet in Newcastle, is handling the arrangements on behalf of his family.

Inspector Morse

Lewis is a sergeant on the staff of the Thames Valley Police in Oxford, England, and in Inspector Morse is assistant to the eponymous Detective Chief Inspector Morse. Although Lewis's given name is Robert (Robbie), he is rarely referred to as anything but "Sergeant Lewis" or "Lewis".

In the novels Lewis is Welsh; in the TV series he is Geordie. His background and personality – a working class, easygoing family man – is frequently contrasted with that of Morse – Oxford educated, RP-accented, and a life-long bachelor. Morse frequently uses these differences to insult or demean Lewis, perhaps from Morse's point of view in a playful manner, but Lewis is often not amused by the jabs. In his frustration, Lewis is often more in step with their joint superior Chief Superintendent Strange, himself an evident supporter of Lewis; however, despite a great respect towards Strange, Lewis is always unflinchingly loyal to Morse and follows his lead. Morse's dying words, said to Strange, are, "Thank Lewis for me."

In Inspector Morse, Lewis is often shown following a hunch that Morse criticises, and in the end Lewis is usually proved correct, or at least more correct than Morse. Near the end of the television series, Lewis moves on in his career and takes a promotion. With the end of Inspector Morse and the death of its star, John Thaw, Lewis's adventures had seemed to come to an end.

In the episode "The Dead of Jericho", Lewis tells Morse "It's also my birthday". The first victim is killed on 11 June, and this utterance occurs a few days to a week later. This puts Lewis' birthday in mid-June.

Lewis does not make an appearance in the episode "The Wench is Dead", because he is attending an inspector's course.

Lewis

In the pilot episode, Lewis returns to Oxford from a two-year stint training police in the British Virgin Islands, following the death of his wife Valerie in a hit-and-run collision in London. Lewis still must work partly in the shadow of the now-five-years-dead Inspector Morse, who sometime prior to his death had worked a case involving one of the murder suspects as a juvenile. In the new series, Lewis gains his own junior, Detective Sergeant James Hathaway (played by Laurence Fox), a Cambridge-educated man who joined the police after giving up training for the priesthood. Another staple of the series, pathologist Dr. Laura Hobson (played by Clare Holman), who appears late in the Morse series, continues on through all of the Lewis episodes as a witty part of the team, with a cynical sense of humour and as a romantic interest to him. In the second series, DS Hathaway discovers that career criminal Simon Monkford inadvertently killed Mrs. Lewis when he lost control of a get-away car after a bank robbery; Monkford pleads guilty to manslaughter.

After Robbie retires (and before he returns to work at the request of their superior, Chief Superintendent Jean Innocent, played by Rebecca Front), Hathaway gains his own assistant, Detective Sergeant Elizabeth (Lizzie) Maddox (played by Angela Griffin). Maddox is black, married, smart, and usually very matter of fact, and occasionally shows a sense of humour in her work with James (and Robbie). In one episode, she is almost killed (an attempted murder by the villain of the episode).

The popularity of the one-off episode spurred the continuation of the story into a total of nine series comprising 33 episodes, the most recent airing in 2015. In the latest series, Lewis had retired from the police force, but is brought back as a consultant to work with Hathaway, who is now a detective inspector himself.