Insomnia, review: Vicky McClure and Leanne Best bravely do battle with shallow potboiler

Vicky McClure as Emma Averill in Insomnia
Vicky McClure's Emma struggles to enjoy a decent night's sleep - Left Bank TV/Paramount Global/Nyree Riding

There is a moment of unintended comedy in the fifth, penultimate episode of Insomnia (Paramount +). A woman caring for her bedridden mother produces a paperback and starts to read aloud. It’s a Barbara Cartland. “They’re all the same,” moans the mother, who wishes for nothing but death.

Not all psychological thrillers on TV are the same. But they tend to rely on a menu of tropes. The uh-oh visuals, the oo-er audio, the humongous house, the unsuspected villain going round the twist. As for the dialogue, it drives plot rather than reveals character and, as often as not, you’re left with a Jenga stack of tottering implausibilities.

Insomnia is not to be confused with, among other Insomnias, the 2002 film by Christopher Nolan. It is adapted by Sarah Pinborough from her own novel about two now adult sisters who have grown up in care after their mother went off the rails, madly repeating numerical sequences.

The insomniac is younger sister Emma (Vicky McClure), a do-gooding lawyer married to the very vanilla Robert (Tom Cullen). They have a cute if troubled little son and a classically stroppy teenage daughter. Emma, who has never told her family that her mother is still alive and in a psychiatric unit, starts to be haunted by nightmares from her childhood, and worry that she is cursed with bad blood, just as her free-spirited arty sister, Phoebe (Leanne Best), wanders back from abroad.

Emma’s rural house and garden are mystifyingly huge, enabling plenty of spooky somnambulism, though none of her night visions will prove as disturbing as the very opening image of the mentally disturbed mother (Corinna Marlowe) thwacking her own head against hard surfaces.

In 2021, Pinborough adapted her novel Behind Her Eyes for Netflix. That this is with Paramount+ means it should fetch up on Channel 5 eventually, the natural home of the potboiler. UK terrestrials might insist on another couple of rounds of script development to make everything, including those baffling numerical sequences, add up.

The plot contains a couple of promising strands – a combustible legal case, a highly inappropriate affair – that go for nothing, plus a shameless coincidence which ushers in the key character of Caroline (Lyndsey Marshal). She’s the one reading Cartland to her mother. The three excellent main performances are stronger than the writing: like good sculptors McClure, Best and Marshal use their skill to carve depths into shallow matter.

Episodes 1 and 2 of Insomnia are available now on Paramount+; one episode a week thereafter