Unforgotten series four review – the coldest of cold cases

A corpse has been found in a junkyard in Haringey, north London, headless and handless, but otherwise preserved like a Siberian mammoth. It has spent years in a freezer in a cellar. Those archaeologists of modern life, house clearance contractors, humped the freezer from cellar to tip when the occupier became an ex-occupier. Welcome to the coldest of cold cases.

Have you ever tried to identify a dead man from a Millwall FC tattoo? Me neither. But that’s the least important question facing DI Sunny Khan (Sanjeev Bhaskar) as the fourth series of ITV’s crime saga Unforgotten begins. Who stashes a corpse where frozen peas should go? Whose body is it? Where’s the head? In Charlton Athletic’s otherwise functionally useless trophy cabinet? It’s too early to rule out the possibility.

Happily, Sunny catches a break in the case as he and DC Fran Lingley (Carolina Main) rummage through obsolete white goods in unbecoming hazmat suits. A Marathon wrapper made from wax paper is found with the body. “Yeah, and?” says Fran’s expression. Marathon, Sunny explains, as if he were setting out the causes of the Peloponnesian war, is what Snickers used to be called before the Great Renaming Betrayal of 1990. If Fran’s left eyebrow could speak, it’d be saying “OK, boomer”.

Late in 2020, Sunny adds, Snickers were temporarily renamed Marathon after 30 years of nominative misattribution. Since that unexpected reboot, Marathons have been produced in plastic wrappers. If Fran’s right eyebrow could speak, it would say, “Is this going anywhere, grandad?” “Of course it’s going somewhere!” say both of Sunny’s eyebrows, albeit nonverbally. The Marathon wrapper indicates that corpse has been in that freezer for at least three decades.

I love how the show’s creator, Chris Lang, captivatingly sketches the lives of four apparent strangers, challenging us to work out what they’ve got to do with the corpse. What might the Buxton family therapist, the flashy Southall businessman, the dodgy boss in Rochester, and the soon-to-be-married woman in Cambridge have in common? They were all Hendon police trainees, yes, but there must be more to the riddle than that. I have my suspicions. Sheila Hancock guest stars as the Cambridge woman’s unpleasantly irascible mother. But if I know anything about six-part dramas and Hancock’s CV, I know that she doesn’t do narratively marginal vignettes.

Like the junkyard corpse, though, Unforgotten is unrecognisable without its head. At the end of season three, our hero DCI Cassie Stuart (Nicola Walker) went on sick leave. She was broken by Alex Jennings’ unrepentantly gurning psychopathic killer from series three and by unravelling mysteries for the Met for 29 years. Now, though, the bean-counters have decided she must return to work for three months before she can retire. If I were one of Cressida Dick’s HR lackeys, I would be livid about this depiction of their employment practices.

But Cassie’s return is good news for us. We get to see the rekindling of the sweetest professional relationship ever to grace TV, that between Cassie and Sunny. She, no doubt, will well up ardently as she puts her minions to work solving this historical mystery; he will be endlessly kind and supportive, while sporting an expression that amounts to men’s answer to Dylan’s Sad-Eyed Lady of the Lowlands.

I’m so invested in Cassie and Sunny’s relationship that when they had a row in season two, I was upset enough to speak unnecessarily sternly to my cat. When they later had a drunken fumble, I considered writing to the producers to complain that they risked replicating boring David Boreanaz and Emily Deschanel in Bones’s ill-judged dalliance, passions seething unacceptably over the cadavers. Thankfully, Lang nipped the romance in the bud. Now, as nature intended, Sunny calls Cassie guv, not love.

Fingers crossed, Cassie’s return will also mean that she will yet again do her Columbo homage, turning bloodhound eyes and mirthless smile on a suspect at the threshold to ask them one last question.

That said, Lang has made a terrible mistake. As far as I can see, he’s plotted season four so there can be no season five, or at least no season five starring Walker. This looks like DCI Stuart’s last case. Three months hence, she will be home caring for her dad who has Alzheimer’s disease, and a live-in boyfriend who is nice, but dull. How Lang proposes to get out of this pickle is a mystery bigger than any his duo have solved. But he must. Unforgotten without Walker is truly Unthinkable.