Unforgotten recap: Everything that happened in series 1-3 of the ITV drama

What cases have Cassie and Sunny been solving? Refresh your memory here ahead of season four

The hit crime drama Unforgotten returns to ITV on Monday 22 February at 9pm for its fourth series, with Cassie and Sunny back on the scene to crack some more cold cases.

If you haven’t been following the show or need a quick refresher, here’s a catch-up of what’s been going on in the past three series – each of which focusses on a different murder case.

***Warning: major spoilers ahead***

Who stars in Unforgotten and what is it about?

Unforgotten follows two refreshingly real London detectives: DCI Cassie Stuart (Nicola Walker) and DI Sunil “Sunny” Khan (Sanjeev Bhaskar) who solve decades-old unsolved murder cases. 

The show, which debuted in 2015, is written by Chris Lang, who also wrote Dark Heart and The Hookup Plan.

Cassie and Sunny are not your typical TV detectives. Lang calls them “extraordinary in their ordinariness”. The drama focuses on the murder cases rather than any personality quirks the pair may have and their relationship is platonic.

Samjeeb Bas (ITV)

The only background details about the characters you need to know are that Cassie lives with her father Martin (Peter Egan) following her mother’s death and has two sons studying at university. Sunny is a single parent raising two teenage daughters after his divorce from his wife. 

The first series (2015)

Cassie and Sunny are called to the cellar of a demolished house where a skeleton has been found. Their only clue to who it might be is a set of car keys found near the remains. 

It leads them to a car where they find a diary in the boot. The diary, inscribed as a gift from someone called JoJo, belongs to Jimmy Sullivan (Harley Alexander-Sule), a teenager from Liverpool who vanished in 1976. It’s soon confirmed the remains are his, but who killed him?

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At home, Cassie is anguished after her father shows her a box of letters he found after her mother died that reveals she had an affair. But she puts tries to put her feelings to one side as she works on the case.

Cassie and Sunny’s team trace contacts in Jimmy’s diary: amongst them are four suspects including wheelchair-bound Eric Slater (Tom Courtenay), a former bookkeeper at Jimmy’s hostel.

Another is Frankie C, aka Sir Philip Cross (Trevor Eve). He has recently been appointed as the government’s entrepreneurial tsar but has a shady past as a mob enforcer for an East End gang. He use to torture people who owed the gang money. We discover that Jimmy had borrowed £50 from the gang to help his friend JoJo get an abortion. 

The third suspect is Lizzie, a woman who stole JoJo’s abortion money from Jimmy. Lizzie, who has a racist past, now helps local disadvantaged young people with her Jamaican football coach husband.

The fourth is a vicar called Father Rob, who was the chaplin at the hostel where Jimmy stayed. It transpires that JoJo, who is thought to be Jimmy’s girlfriend, became pregnant with Father Rob’s baby when she was 15 years old. He stole parish funds to support her and the child. The question arises: Did Jimmy have a violent confrontation with Father Rob that could have led to the teenager’s death?

Unforgotten series one (ITV)

Cassie and Sunny rule everyone out except for Eric, who has a past conviction for a homophobic attack. While Jimmy wasn’t gay, he had been a sex worker, and the detectives decide to investigate further.

All hell breaks loose when a corpse of a gay man is found in Eric’s back garden after a tip off from his son, and Eric is charged with both murders. 

But Cassie doesn’t believe Eric is guilty and she’s quite right. The real killer is Eric’s wife Claire.

Eric admits to the police that he is a closeted gay man and his jealous wife, who was suffering from post-natal psychosis, murdered his male lovers when she caught them having sex.

Eric buried both bodies to help her avoid arrest.

The second series (2017)

The gruesome remains of a Tory party fundraiser and club promoter David Walker (Daniel Gosling), who disappeared in 1989, are found inside a suitcase in the River Lea. Cassie and Sunny identify the corpse by tracing repair work carried out on David’s flashy watch. 

The pair hone in on several suspects including David’s widow DI Tessa Nixon (Lorraine Ashboure), a passionate copper in Oxford who has remarried. She has a stepdaughter and a troubled 30-year-old son, called Jason. 

Another suspect is a Brighton-based barrister, Colin Osbourne (Mark Bonnar), who is adopting a six-year-old girl with his husband, Simon, and is being blackmailed by the birth mother. He has no obvious link to the victim but has clearly got anger issues.

The third suspect is paediatric nurse Marion Kelsey (Rosie Cavaliero). Her husband Tony is concerned about her mental health.

And the fourth is a schoolteacher, Sara Mahmoud (Badira Timini), who admits that David may have been one of her clients when she worked as a sex worker in a brothel a long time ago. 

Mark Bonnar in Unforgotten series 2 (ITV)

When the detectives find out that David was sexually abused as a child, they incorrectly think he died confronting his abuser.

Cassie’s father and Sunny are meanwhile both trying to date online with little success. Cassie finds out her father went to Winchester to find the man who had an affair with her mother. He gets closure when the man sends him a letter proving that she ended the affair. Sunny lunges in for an ill-judged kiss with Cassie that is quickly rebuffed and they agree to keep things platonic.

When links are discovered between barrister Colin, who donated to the Tory party in the 1980s, and David, the mystery begins to unravel. Colin left his banking job and had a breakdown after David got a female employee to falsely accuse Colin of rape. Clearly David wanted Colin out of the picture because he was getting too nosy. Colin was led to believe he had raped the woman during an alcoholic blackout, but actually she had been paid £5,000 to get him drunk.

Soon, it becomes clear that David was a paedophile who used his links to children’s charities to attack his victims. We discover that Sara, the schoolteacher, was raped as a young teenager by David at parties where he would drug vulnerable children. 

Cassie figures out that Sara, the nurse Marion and the barrister Colin all know each other and are all victims of child sexual abuse. They met in a psychiatric ward and made a deal to take revenge on each other’s childhood abusers.

Marion killed Sara’s abuser, David; Sara killed Colin’s abuser, Len Paxton; and Colin killed Marion’s abuser, her father.

Cassie wants to spare them jail; they have suffered so much. Sunny supports her. They turn a blind eye and don’t press charges.

The third series (2018)

Cassie and Sunny are on the hunt for the serial killer and rapist responsible for the murder of schoolgirl Hayley Reid (Bronagh Waugh) who vanished from a seaside town on New Year’s Day in 1999. Her remains were discovered in London by workmen as they repaired part of the M1 motorway in London.

Four friends renting a holiday home at the same time and location of Hayley’s murder become suspects.

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One is the TV quiz show host Jamie Hollis (Kevin McNally). It turns out he thinks his troubled son Elliott killed her in a drink driving accident; something he has been covering up for 18 years. 

Another is house guest Chris Lowe (James Fleet), a struggling artist who lives out of a van with his dog. His daughter tells Sunny about his child porn charge that was later dropped by the police as it was paid for on his stolen credit card. 

The third is insurance salesman Pete Carr (Neil Morrissey). He spent time in a Hong Kong jail for defrauding a charity and admits to a robbery at a church in Middenham on the night Hayley was murdered nearby. 

He gets stabbed when his past is exposed after Cassie accidentally leaves his file in a café. When he dies, Cassie’s job is on the line. 

The final suspect is the beloved GP Dr Tim Finch (Alex Jennings). He had been investigated for abusing an elderly patient, but at first there is nothing to suggest he’s the evil killer. 

That’s until a speeding ticket pinpoints the GP racing out of Middenham on the 3 January 2000 on his way to London. This clue leads to his arrest on suspicion of Hayley’s murder. 

Alex Jennings in Unforgotten series 3 (ITV)

A scrunchie, a necklace and underwear are found during a search of his house. He says they were bought at a fete for his daughters, but DNA results reveal they belonged to Alison Baldwin, a 14-year-old from Cambridge, who was found raped and strangled in 1997. He later makes a chilling confession to the killing of Hayley.

The revelation that Finch is a cold psychopath affects Cassie badly, and she takes a sabbatical to recover and give her romance with DCI Bentley (Alastair MacKenzie) a proper go.

The series ends with Cassie and Sunny bringing flowers to Hayley’s final resting place at a memorial garden.

And now for series four…           

Filming for the latest series resumed in September 2020, following a hiatus due to the Covid pandemic. 

In the new episodes, Cassie is upset when her plans for retirement from the police force, for her “own sanity and wellbeing”, are thwarted just as her father’s dementia is worsening. 

She learns she isn’t entitled to her full pension payment unless she completes her 30 years of service. 

Cassie is gutted, but decides to return to work and join Sunny who is investigating the case of a headless body found dumped in a north London scrapyard. It’s frozen rock solid – has it been stored in a domestic freezer for decades?

And who is the culprit of the latest murder? You’ll have to wait and see.

All three season of Unforgotten are available on Netflix. There is also access to season three on the ITV Hub.