Mischa Barton is the unexpectedly canny flower-bothering sleuth here in a not very mysterious costume thriller

Serviceable but underwhelming, this murder mystery is very old-school in every way, reminiscent of many an Agatha Christie page-turner and even more so of Christie’s innumerable imitators. It’s like someone used AI to write the script, plugging in parameters such as “set it in the 1930s”, “plucky Englishwoman protagonist” and “ethnically diverse cast of supporting characters/suspects”.

And so we have Mischa Barton playing Miranda Green, a florist by trade and naturally an avid reader of Christie; she gets a mysterious invitation and train tickets to visit the home of textile magnate Lord Findlay on an island. On the train, Miranda meets several other guests, all as bemused as she is at the invite: rangy and rude Yank Walker (Chris Browning), smooth Brit lawyer Lawrence Kane (Seamus Dever), Spanish waitress Carmen Blanco (Bianca A Santos), posh doctor Phillip Armstrong (Giles Matthey) and soignée Chinese visitor Lu Wang (Grace Lynn Kung). However, when they all arrive at the big creepy mansion, the servants regretfully inform them that their host has been delayed, so they pass the cocktail hour playing Two Truths and a Lie. Miranda, of course, turns out to be a crack player, so much so that you’d think the others would object more to the rudeness of her triumphant calling out of each lie. Later, bodies turn up, inspectors are called, secrets are revealed.