Nicola Walker is one of those stellar actors you can always rely on to star in brilliant TV shows. From the brand-new Alice and Steve to, of course, The Split, she's also starred in a series of gripping thrillers.
And while Unforgotten might already be on your radar, did you know Nicola Walker starred in the earlier seasons? Her character Cassie was a core part of the first four series, before the show's creator decided she had reached her natural conclusion.
Here's what you need to know about Unforgotten, from the premise to the show's future, and where you can watch existing episodes now.
What is Unforgotten?
Unforgotten follows a team of police detectives who are tasked with investigating cold cases and disappearances that haven't been solved. While the series has a focus on the murders themselves, it also looks at the impact these crimes has on the individuals who are left behind, and how buried secrets can change their lives all these years later.
Who did Nicola Walker play in Unforgotten?
Unforgotten was a real hidden gem for the actor, who appeared in the first four seasons of the show. She played DCI Cassie Stewart, a lead police officer in the Metropolitan Police who worked closely alongside her second-in-command, Sunny Khan.
She lived with her father and two adult sons, and met a tragic end in season four when she had a fatal car accident. She eventually died from brain injuries, leaving her team in mourning.
Speaking to Radio Times about the decision to retire her character in the show, Nicola explained, "I’ve worked with [Unforgotten creator] Chris Lang more than any other writer and we are friends. From the very beginning, we talked about Cassie’s story being finite; Chris was always putting her through a story arc that would damage her emotionally.
"The buzzword was that she was an empath, and the problem with being an empath is that eventually, you break. I felt that to have her keep coming back would make her seem like a superhero. So it was very much a joint and long-planned decision."
How many episodes of Unforgotten are there?
There are six episodes of Unforgotten per season, and there are currently six seasons of the show - meaning you can binge-watch a massive 36 hours of TV if you've never watched an episode. Nicola Walker starred in 24 episodes of the gripping series, until February 2021, before her character was replaced by Sinéad Keenan as DCI Jessica James.
Where can you watch Unforgotten?
All 36 existing episodes of Unforgotten are available to watch on ITVX.
What is the future of Unforgotten?
Huge news! In January 2026, ITV revealed a seventh season of Unforgotten was in the works, and it would be long before fans were treated to more episodes. The synopsis for the next instalment says the series will focus on "the chilling discovery of human remains in the crawl space of a house in Ladbroke Grove, London. Early forensic analysis suggests the body is that of a child and has been deliberately concealed for several years.
"The investigation takes a deeply personal turn for the team when a DNA match links the victim to a previously closed historic case, compelling DI Sunny Khan and DCI Jess James to revisit the original inquiry and unravel the truth behind a decades-old crime."
