This delightfully idiosyncratic, sun-kissed mystery serves up a fantastic leading role for Sam Riley, who first grabbed our attention in 2007’s Ian Curtis biopic Control but hasn’t always had the best material to work with since. It tells the story of former English tennis pro Tom (Riley), now coaching holidaymakers on an unnamed Canary Island (the film was shot on Fuerteventura). We see how he lives his life as if on permanent vacation and bounces between lacklustre, painfully hungover lessons and a hardcore party lifestyle, waking in unexpected locations and indulging in a succession of one-night stands.

Things get thrillingly sticky when Tom is drawn into the orbit of an affluent English couple, Anne and Dave Maguire (Stacy Martin and Jack Farthing), who are holidaying on the island, much to the snobbish Dave’s displeasure. There’s an instant attraction between Tom and the irresistibly ambiguous Anne, a former (though not especially successful) actress, with Dave seemingly oblivious to said frisson, as he grapples with depression and shows a total disinterest in parenting his son Anton (Dylan Torrell).

When Dave goes missing following a wild night out with Tom, an investigation ensues. It’s initially led by Tom’s police buddy Jorge (Pep Ambròs), before the infinitely more suspicious Inspector Mazo (Ramiro Blas) rocks up ('He’s a bored cop from the capital, who’s spent too much time watching Columbo on TV,' is Jorge’s withering verdict). Eternal outsider Tom is a captive audience to the Maguire family’s domestic disputes (which, as an escapee from any semblance of normality, he has studiously avoided for himself). However, there is something deeper and more disconcerting afoot, as the extent of Anne and Dave’s relationship troubles reveals itself and Tom begins to truly wake up and experience a sense of déjà vu about her. Playing on the idea that no man is ever really an island, as well as the proximity and disconnect between island groups, German filmmaker Jan-Ole Gerster riffs on some of the conventions of film noir (the slippery, subtly charismatic Martin makes an excellent and thoroughly modern femme fatale, for example).

There’s also more than a smattering of Patricia Highsmith about proceedings, and just a pinch of the exotically set Agatha Christies. And yet, if you like your mysteries with an askew, indie flavour then this should appeal too; Gerster directs with a discreetly amused eye in his pursuit of a dishevelled protagonist, throwing in some random camels, one of whom, like Tom, struggles to stick with the flock.

Riley is marvellous at the fore, imbuing this morally dubious, directionless character with pathos and decency as he feels the lure of reuniting with reality. The faded glory of the oddly anomalous hotel complex, and the island’s rugged, volcanic landscapes and desolate deserts, are strikingly captured by cinematographer Juan Sarmiento G. And the whole enterprise benefits from bags of laid-back charm, a wonderful fit for a misguided yet inherently affable hero, who just cannot resist getting sucked into trouble.

Islands is in cinemas from Friday 12 September.