Channel 5's The Castaways reminds us why Sheridan Smith is one ...

Watching The Castaways, Sheridan’s Smith’s latest mystery thriller, it’s hard not to think of that last major plane crash drama, Lost. Creator and writer Ben Harris’s attempt to emulate the hit noughties drama – albeit on a 2020s budget – is obvious. And though it never lives up to those lofty, multi-Emmy-award-winning standards, it’s a light and pulpy addition to the crime caper genre.

The Castaways might have initially aired on moneyed streamer Paramount+, but it feels far more at home on Channel 5, where it’s now landed. This is a gripping if lightly implausible drama, with a calibre of acting talent – most notably Smith, who elevates any drama she touches, no matter how trashy – that belies the low production values and hokey effects. 

Based on Lucy Clarke’s novel of the same name, The Castaways – just like Lost – follows a flight that mysteriously vanishes and shows up on a remote island near Fiji. Yet the episode opens with a tableau ripped straight from another modern mystery thriller: The White Lotus. While a female voice wails on the soundtrack, a woman’s body floats in the vibrant turquoise water, blood curling around her in the blue, like plumes of smoke.

That’s in one timeline, anyway; as with many a modern mystery drama, the action flits between two. In the present day, formulaically sign-posted as the word “NOW” melts across the screen in white capital letters (sans serif font, naturally), we meet Erin (Celine Buckens).

A young woman with a shaggy black haircut, Erin sits alone in her room. Photos, documents and post-it notes are pinned to her walls and linked together by string (yes, really), and a conspiracy theory video essay about a missing plane plays in the background from her computer beside a cardboard box labelled “Lori’s stuff”.

As viewers, we are forced to make like Erin and piece together what’s happening. After all, Harris’s script ricochets between a staunch refusal to hold your hand and a need to tightly grasp it to shove in some exposition.

Erin, we deduce, is the sister of Lori (Smith), a woman who went missing with her flight from Fiji. She’s still living with Lori’s husband Daniel (Dominic Tighe), but the pair clash, and not just because Daniel has a new life and partner.

Daniel and the families of the other victims are being encouraged to take an insurance settlement over the missing flight. But ever the black sheep of the family, Erin isn’t taking it.

How could this flight just “vanish into vapour”, she asks, wide-eyed, “but now that the insurance companies want to wrap this up, a piece of the wreckage just appears.” Erin is certain: “I just know that plane is out there. My sister’s alive, I can feel it.”

The tension between Erin and Daniel simmers in the present day, a place always shown through cold, murky tones. There’s little subtlety in the contrasting warm hues and high saturation filter that wash over the flashback scenes – or “THEN” – but darkness lies beneath there, too.

Soon, we learn that Erin was supposed to be on that fateful holiday in Fiji with Lori. But at the airport, Lori keeps getting her sister’s voicemail, and she is forced to fly alone, revealing to another passenger that the siblings had had a “bad” fight. Her seat neighbour smiles. “You’re sisters. You’re going to find a way to make it up.”

Of course, that doesn’t happen. The flight hits turbulence, in a prolonged scene that ramps up the tension. Up until this point, Smith has felt underused, but here she reminds us why she’s one of the UK’s most bankable TV stars. A look of true fear clouds her eyes, and soon she’s gripping her seat, hyperventilating and crying like she does best.

Despite the stock storyline, there’s still enough here to keep me watching The Castaways, if only to see Smith stretch her acting muscles further. Those looking for a sophisticated new drama shouldn’t expect much, but fans of the genre will find more of what they love here. Nervous flyer? Probably give it a miss…