Unforgotten series four, episode one recap – one more for the road?

A lesbian, a businessman, a family therapist and a Sikh man get in a car – it sounds like the setup for a Bernard Manning gag. The punchline comes 30 years later, when a Millwall fan’s defrosting body shows up in a scrapyard, minus hands and head. Unfortunately for the killer, it’s on the patch of some seriously tenacious plod who love nothing more than cracking a stony cold case.

Soulless bean counters have forced Cassie (Nicola Walker) back in the game, and with her father (Peter Egan) in the early stages of rapid onset dementia, she can ill-afford to forgo the £124,000 three more months of service will earn her. Although Martin’s verbal cruelty (a symptom of his illness) works her last nerve and she resents returning to the scene of the crime(s), her relationship with John is still on and looks pretty solid.

The investigation

Here’s what we know. The body currently on slow thaw in the morgue is that of Matthew Walsh, fan of Marathons and Millwall FC. The apprentice electrician was 24 when he was last seen at around 11pm on 30 March 1990 in West Hendon. Within a mile of that sighting and on the same night, Robert Fogarty was busted for drink-driving a car carrying our four suspects, a group of newly qualified police officers, returning from their passing-out celebration. Matthew’s body was stored in Fogarty’s fridge, dumped by the council after his death.

It sounds like a hastily covered-up vehicular manslaughter but we can be certain there is a lot more going on than that. It’s lucky we’ve got our best woman on the case. Cassie returns like a retired safe-breaker back for one last heist, assuring Sunny that she’ll just do the job and “not get too involved”. Whatever you say, guv.

Ram Sidhu

Things look good for Ram (Phaldut Sharma), as he visits his folks in Southall, west London, an area dubbed “Little Punjab”. He loves his mum, is respected in the community, and his wife is pregnant. If we were to pick holes in his life we might point out the query the ultrasound operator raises with a colleague after she scans the foetus. Then there’s the day, 40 years ago, that he mentions to his brother when they “first showed them we weren’t the smiley waggly-headed It Ain’t Half Hot Mum twats they wanted us to be”. This is likely a reference to a riot in Southall in 1979 after the National Front booked a meeting at the town hall. “We both know it ain’t over,” he says ominously. Wait until you find out who’s just turned up in a freezer; then we can talk about what ain’t over.

Liz Baildon

It’s that time of year when we put a Sunday aside for our awesome mums. For Liz (Susan Lynch), though, it feels like every day is Mother’s Day. Bedridden and bitter, with a tongue that could shred lettuce, Liz’s mum Eileen is best described as challenging. Liz’s fiancee Janet prefers “evil old cow”, and while carer Eugenia hasn’t gone that far, she is definitely going to need a payrise if she’s going to keep babysitting the dragon upstairs. With an upcoming wedding and a looming care crisis, the last thing Liz needs is a dead Millwall fan stinking her life out, but show me a wedding that hasn’t had the odd planning hiccup.

Fiona Grayson

Family therapist Fiona (Liz White) is kindly and wise. “If we lie to the people closest to us,” she tells one of her clients, “it stops people knowing us or being able to understand us.” If ever a sentence was built to come back to haunt you this was it. Still, she and her partner Geoff seem happy enough in the gorgeous Peak District, living together with his kids. There’s a twinge of concern about a visit to see Geoff’s brother over some mortgage issues, but it doesn’t feel major. The kids’ mum is still in the picture in some form and we learn that Fiona never knew her own parents. As much as anyone, she knows the importance of family.

Dean Barton

You might say the same for Dean (Andy Nyman), who dotes on his disabled son Jack and looks happy with his wife, Marnie. We meet him in the middle of a charity commitment but his main gig is running his business, DB Atmospherics. So far, so respectable – but a shady past resurfaces when a certain Felix phones asking for help with “a massive shipment” at Calais that sounds very much under the table and off-the-books. It’s been 11 years since Dean’s done any of that kind of thing so it’s absolutely out of the question. Unless, of course, he’s one of those high-risk high-reward types we hear about.

Notes and observations

• The show’s creator, Chris Lang, has said that “the primary theme of this series will be society’s relationship with the police,” which sounds like we might be uncovering some skeletons in the Old Bill’s cupboard.

• Cassie cites her decision to not prosecute the murders stemming from the Walker case, the horrors of Tim Finch and about a thousand other things in her decision to walk away. Now she’s back, though, will it be for good?

• Millwall FC’s proud history of anti-Marxism is quite well documented. Ram butting heads with Matthew at some point in his past must be a live possibility.

• I loved Sunny’s look of longing at Cassie’s empty chair. No one does it like the gaffer.

Where is Matthew’s head? Can Cassie avoid getting too involved? Who is your early hunch for the killer? Please place your most absurd and unsubstantiated theories in the comments below.