Unforgotten season 5: How did season 4 end, who’s replacing Nicola Walker as DCI and what to expect from the new series of the intense ITV drama

Unforgotten season 5 will see a new DCI take Cassie's place in the team as they tackle a particularly intriguing cold case...

All we know about Unforgotten season 5. Seen here are Sunny Khan and Cassie Stuart in Unforgotten
(Image credit: ITV)

Unforgotten season 5 is fast approaching and after the heart-wrenching season 4 finale the ITV drama will see a brand new DCI follow in some iconic footsteps.

Ever since the devastating season 4 finale and tantalizing Unforgotten series 5 first look from creator and writer Chris Lang, fans might well have been asking themselves one key question - when is Unforgotten coming back? We’ve had to be patient for almost two years waiting for the ITV drama’s triumphant return but now a release date for Unforgotten season 5 has finally been confirmed. DI Sunny Khan will soon back solving cold cases with his team, though there’ll be one major absence. 

Here we unveil our whirlwind recap of how Unforgotten season 4 ended, who’s replacing Nicola Walker’s DCI Cassie Stuart and what you can expect from Unforgotten season 5…

*Warning: Spoilers ahead*

How did Unforgotten season 4 end? A whirlwind recap of the last season 

Fans could be forgiven for wondering how exactly Unforgotten season 4 ended as it’s been quite some time since the show was on our screens. The fourth season followed the investigation that followed the discovery of Matthew Walsh’s headless and handless corpse 30 years after he went missing. But whilst this was the primary storyline crime-wise, just like we’ve seen in everything from Happy Valley season 3 to Shetland season 7, the crimes are only part of the story. 

The personal lives of DCI Cassie Stuart (Nicola Walker) and DI Sunny Khan (Sanjeev Bhaskar) are every bit as significant and in terms of ongoing plotlines that could influence Unforgotten season 5, perhaps more so.

Cassie returned to the force in season 4 after going on medical leave in season 3. Although fans might’ve hoped she’d get her happy ending with boyfriend DCI John Bentley, Unforgotten season 4 ended with Cassie’s death following a car accident. 

This happened in episode 5’s concluding moments, leaving fans anxiously awaiting news of her fate - as was Sunny. She was rushed to the hospital where Sunny, John, Cassie’s son Adam and her father Martin waited for news. 

Initially things looked optimistic and Sunny returned to work on the Matthew Walsh case and continued questioning suspects. After following-up on one of Cassie’s leads, Sunny realized that suspect Dean Barton had killed Matthew in revenge for Dean’s brother Stephen being killed by Matthew. He even tracked down the car thief who’d been involved in the collision with Cassie’s vehicle.


(Image credit: ITV)

But any sense of victory dissipated fast when Sunny was told that Cassie had sustained far more severe brain injuries during the crash than doctors had thought and wasn’t expected to recover. The final scenes of Unforgotten season 4 showed Sunny delivering a powerful eulogy at his late colleague’s funeral in which he declared, “Cass Stuart was my colleague. She was my mentor. She was my friend, and I loved her.”

Sunny then visited her grave - engraved simply, Mother, Daughter, Copper. This grave-side moment of reflection had parallels to the closing stages of the Happy Valley ending and concluded Sunny and Cassie's friendship story together incredibly profoundly ahead of the upcoming Unforgotten season 5.

Why did Nicola Walker leave Unforgotten and who’s replacing her? 

The moment Nicola Walker left Unforgotten likely left many fans in tears but according to the star, whose performance as high-flying lawyer Hannah in The Split season 3 ending was just as brilliant, her departure was planned from season 3. Getting candid with TV Insider she said that it was something she talked about a lot with Unforgotten creator and writer Chris Lang. 

“We were talking from the beginning, really, about what he was doing with this character and this story he wanted to tell. Chris and I were always interested in looking at the cost of being involved with these sorts of cases that we all love watching on television,” she said.

Nicola Walker arrives for the Lawrence Olivier Awards

(Image credit: LEON NEAL/AFP via Getty Images)

Nicola added, “Cassie does not have superpowers. She’s an ordinary person who’s really good at her job, and it took her to the place of having an emotional breakdown.”

She also expressed her belief that the “clues were there” in season 3 that Cassie’s journey was reaching a natural end, but that - very appropriately - DCI Cassie Stuart won’t be forgotten. 

“We talked a lot after Season 3 about where it was going to go, and it was a joint decision. I think the clues were there in Season 3. The title of the show is Unforgotten and I think there’s a great deal of narrative beauty to this woman," the actor shared. "She’s not going to be forgotten. I felt like she was quietly very unusual on television because she was a real person.”

SINEAD KEENAN as DCI Jessica James and SANJEEV BHASKAR as DI Sunny.Khan.

(Image credit: MAINSTREET FOR ITV)

Going forwards in Unforgotten season 5, Cassie’s place as one of the main two detectives is being filled by the wonderful Sinead Keenan. She’s set to play DCI Jessica ‘Jessie’ James who will be Sunny’s new detective partner. Fans might recognize Sinead from her roles in everything from BBC’s Showtrial to Derry Girls and we’re excited to see how Jessie fits into the new series.

When does Unforgotten season 5 start? Release date and all we know so far 

After the emotional rollercoaster of season 4 - not to mention the long break between seasons - fans might be eager to see what Unforgotten season 5 has in store when it lands on Monday February 27 at 9pm on ITV1 and it will also be available to stream on ITVX. 

We already know that Jessie will be making her Unforgotten debut and according to Sinead, things aren’t going smoothly for her character in her personal life as she starts her brand new job with Sunny. Her marriage had fractured on the morning of her very first day and apparently it’s not just viewers who might be comparing Jessie to Cassie.

Sinead Keenan attends the ITV Palooza

(Image credit: Photo by Karwai Tang/WireImage via Getty)

Opening up to the Telegraph ahead of Unforgotten season 5, Sinead explained, “With the team, she’s constantly measured against the brilliance of Cassie, and their love for her: ‘You picked this eejit?’ And the audience will be doing the same.”

In terms of the storyline of Unforgotten season 5 (new DCI aside), the new series will focus on the team’s investigation after human remains are discovered in a renovated property in Hammersmith. They then have to determine if the murder really took place in the 1930s or whether the victim could’ve been disposed of much more recently. 

Although the loss of Cassie Stuart will likely still be felt deeply in Unforgotten season 5, there will also be plenty of familiar faces alongside Sunny Khan. The cold case investigations team will be back in action, including Jordan Long as DS Murray Boulting, Carolina Main as DC Fran Lingley, Georgia Mackenzie as pathologist Dr Leanne Balcombe and Pippa Nixon as DC Kaz Willets. Sunny’s partner Sal will also return, played by Michelle Bonnard.  

How to watch Unforgotten seasons 1-4 

If you haven’t yet dived into Unforgotten, or maybe you just want to re-watch your favorite moments before Unforgotten season 5 starts then ITVX is the place to go. All episodes of the crime drama are available to stream now. For US-based Unforgotten fans, episodes are available to watch via Amazon Prime Video and PBS. 

Sadly, if you're abroad on vacation when you want to watch Unforgotten then you won’t be able to watch like you normally would due to regional restrictions. Luckily there’s an easy solution and you can use a VPN to continue watching. This is a handy bit of software that changes your IP address so that you can access on-demand content or live TV just as if you were at home.

Our sister site, TechRadar, has tested all of the major VPN services and they rate ExpressVPN as the absolute best. They say, “It’s compatible with all of your devices, supports most streaming services, and ranks among the fastest. You can even install it on devices like an Amazon Fire TV Stick, Apple TV, Xbox, and PlayStation. So for a one-stop-shop, you can’t go wrong with Express.”  


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If you've never installed a VPN before, don't worry, it's quick and easy. Just follow these three steps:

  1. Download and install the VPN following ExpressVPN's easy-to-follow instructions.
  2. Once you've installed your VPN, open the app and select your server location as anywhere in the UK.
  3. With your VPN installed and server location set to UK, you can now watch Unforgotten online. 

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(Image credit: Future)
Emma Shacklock

Emma is a Royal Editor with eight years experience working in publishing. Her specialist areas include the British Royal Family, ranging from protocol to outfits. Alongside putting her royal knowledge to good use, Emma knows all there is to know about the latest TV shows on the BBC, ITV and more. When she’s not writing about the next unmissable show to add to your to-watch list or delving into royal protocol, Emma enjoys cooking, long walks and watching yet more crime dramas!