Endeavour returns to our screens for its final series in 2023 and while it may be coming to an end, season 9 promises some enthralling cases for Morse to investigate with the cast of episode 1 welcoming a host of suspicious guest stars.
It’s been a whopping 17 months to the day since Endeavour last aired on ITV and the increasingly world-weary Morse finds himself called back into action after he was given a leave of absence at the end of the last series.
However, it quickly becomes clear that this latest case will be another tough nut to crack as Oxford finds itself at the heart of some deadly business brought in by the London criminal underworld.
Endeavour season 9 episode 1 release date and plot preview
Episode 1 of Endeavour season 9 will arrive on ITV at 8pm on Sunday, February 26, 2023.
Titled Prelude, the new series of Endeavour kicks off in the spring of 1972 and sees Morse rejoining Thursday after his leave of absence.
They have been called to investigate a murder in a college garden which puts the pair on the tail of the celebrated Oxford Concert Orchestra, which is led by famed composer Sir Alexander Lermontov.
A web of secrets slowly starts to unravel as the detective duo continues their investigations and when a second tragedy strikes, it soon becomes clear that business involving the grisly London underworld is threatening to turn Oxford into a blood bath.
The case is made even more unsettling, however, when Morse and Thursday begin to realise that there are some alarming ties that link their current investigation with one that they hoped was long since behind them.

Endeavour season 9 episode 1 cast
As ever in Endeavour, the murder mystery welcomes back its central cast of characters while also introducing a host of guest stars and that is certainly the case in episode 1.
Main and recurring cast
- Shaun Evans as DS Endeavour Morse
- Roger Allam as DCI Fred Thursday
- Anton Lesser as Chief Supt Reginald Bright
- James Bradshaw as Dr Max DeBryn
- Sean Rigby as DS Jim Strange
- Abigail Thaw as Dorothea Frazil
- Caroline O’Neill as Win Thursday
- Jack Bannon as Sam Thursday
- Sara Vickers as Joan Thursday
Guest stars
- Imogen Daines as Mabs Portman
- Nicholas Farrell as Sir Alexander Lermontov
- Simon Harrison as Ronnie Box
- Jane Lapotaire as Madame Belasco
- James Anderson as Fergus Brathwaite
- Nicholas Boulton as John Graham-Scott
- Rob Ostlere as Donald Fischer
- Leaphia Darko as Lindsay Trench
- Tamsin Newlands as Margeaux Quincannon
- Kirstin Louie as Christina Poole
- Jenny Galloway as Mrs Pat Treadle
- James Doherty as Mr Lee

Guest star spotlight
Imogen Daines as Mabs Portman
We begin our cast rundown for episode 1 with Imogen Daines who takes on the role of Mabs Portman.
The actress has appeared in 14 roles since making her debut in 2012 with her most notable appearances coming in the likes of Chasing Shadows, Black Mirror, On Chesil Beach, Intergalactic, The Witcher, Killing Eve and most recently, the Aidan Turner-starring The Suspect.
Nicholas Farrell as Sir Alexander Lermontov
Undoubtedly the most familiar guest star in episode 1 will be Nicholas Farrell who appears as the illustrious composer, Sir Alexander Lermontov.
The Essex-born actor has starred in almost 150 roles over an almost 50-year career with some of his most familiar coming in the likes of Chariots Of Fire, Mansfield Park, Poirot, Casualty 1909, Inspector Lewis, Death In Paradise, Mindhorn, White House Farm, The Crown, Silent Witness, Munich: The Edge Of War and Gentleman Jack.
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Simon Harrison as Ronnie Box
Simon Harrison will be familiar to murder mystery fans as he recently appeared in an episode of ITV’s Vera while he also reprises the role of Ronnie Box which he last played in season 6 of Endeavour.
Harrison’s other credits include appearances in His Dark Materials, This Is Going To Hurt, Outlander and the 2015 film, Everest.
Jane Lapotaire as Madame Belasco
With an acting career dating back to a 1968 episode of Sherlock Holmes, Jane Lapotaire will be a familiar face to many with the actress appearing in the likes of The Devil’s Crown, Love Hurts, Downton Abbey, The Crown, Channel 5’s Dalgliesh, ITV’s Lucan and Netflix’s 2020 adaptation of Rebecca.

Nicholas Boulton as John Graham-Scott
Nicholas Boulton has more than 100 roles to his name, many of which have come from voicing characters in video games such as Lego Star Wars: The Skywalker Saga, A Plague Tale: Requiem, Hitman, Dragon Age: Inquisition, several entries of the Assassin’s Creed franchise and many more.
However, in the world of film and TV, fans may recognise the actor best for appearing in Casualty, Game Of Thrones, Midsomer Murders, Doctors, Jonathan Creek, Arn, and Life Begins among others.
Rob Ostlere as Donald Fischer
Rob Ostlere is another veteran of Game Of Thrones, although his role is only a brief one as he plays one of the unfortunate members of the Night’s Watch who are butchered by White Walkers in the very first scene.
Other projects that the actor has appeared in include I Hate Suzie, The Vessel, The Chelsea Detective and most notably, Holby City, where he played Arthur Digby between 2013 and 2022.
Jenny Galloway as Mrs Pat Treadle
Jenny Galloway is another actress with an impressive list of projects on her acting CV as she’s starred in the likes of The Split, The Queen’s Gambit, Good Omens, Mamma Mia: Here We Go Again, Silent Witness, Fleabag and Johnny English among others.
James Doherty as Mr Lee
And finally, we end with James Doherty who is an actor with 80 credits to his name, with notable roles coming in Outlander, Queens Of Mystery, Apple TV+’s Trying, Close To Me, Coronation Street, Call The Midwife, The Windsors, Him & Her and Night & Day.

Endeavour season 9 episode 1 arrives on ITV at 8pm on Sunday, February 26, 2023.
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