Cheat, Monday 9pm, STV

The four-part psychothriller Cheat opens with a brief, teasing, flash-forward in which the lead characters, Cambridge sociology lecturer Leah Dale (Katherine Kelly) and her twenty-ish student Rose Vaughan (Molly Windsor), face each other through the glass divide of a dim prison visiting room, hostility crackling like static.

But it was only halfway through the first episode that it dawned on me that I didn’t know which of them was visiting, and which was the prisoner.

Written by Gaby Hull, the drama has a fair few tricksy, surprising moments like this. At the same time, though, a lot of what happens is highly predictable.

Still, as it draws its mystery out, it’s all nicely nasty enough to keep you hooked, and is carried over any bumps by the performances of Kelly and Windsor.

Leah and Rose quickly line up as enemies, but, as that opening image suggests – the pair facing off on either side of a thin glass wall – in some respects they mirror each other.

Most obviously, both tutor and student have had to deal with the suspicion that each won her place at university not through her own merit, but thanks to the unspoken influence of her father.

Leah’s dad (Peter Firth) is a well-established veteran lecturer at the place, while Rose’s millionaire father (Adrian Edmondson) has been responsible for a colossal amount of recent funding.

Possibly, though, the women’s biggest doubters are themselves. Certainly, Leah, despite her bright, brisk manner and her impending promotion to a permanent position, has a chip nagging away on her shoulder.

As a result, she’s determined not to give anyone a free ride, and especially not Rose.

Irked by Rose’s slack attitude in class, her habit of showing up late, refusal to contribute, and air of never listening, Leah reaches the end of her tether when Rose hands in a dissertation.

It’s not that the essay is bad. Rather, Leah reckons it’s far, far too good to have been Rose’s work at all, and marks it a Fail, for suspicion of cheating.

From here, things escalate quickly, as Rose goes out for revenge, launching on an obsessive scheme to destroy not only Leah’s reputation and career, but her entire life.

She begins by focusing on the stresses in Leah’s marriage – her relationship with husband Adam (Tom Goodman-Hill) is under strain as a result of recent, fruitless attempts to have a baby.

Before long, as the acid feud unfolds, there comes another sudden flashforward: police zipping a corpse into a bodybag.

Some of these narrative gimmicks feel like a failure of nerve.

Instead of telling the story straight, drawing the audience in with a slow, steady reveal, the show flashes forward to reassure us, don’t worry, there’s violence coming.

Cheat might have been more interesting if, instead of the killer stuff, it stuck on the question of whether Rose really was cheating academically, or whether Leah had got it wrong.

As it is, it gives away a little too much too early, and plays out like a feminine spin on Cape Fear, with Rose as the unstoppable, vengeful force out to wreck Leah’s comfortable existence, aided in part by Leah’s own failings.

But it’s a decent way to kill a week, with a fine cast, including Burn Gorman, who can still disturb a scene simply by appearing. Kelly – one of our greats, who still hasn’t quite found the screen role she deserves ­– and Windsor, confirming the astonishing talent displayed in Three Girls, are excellent.

As they join in a tight, toxic waltz, the chance to watch them is almost enough to justify the decision to run the entire series over four consecutive nights.