Filmmakers don’t get brownie points for sticking close to formula when tackling a genre picture. But if they did, Kim Farrant could collect hers for “The Weekend Away,” a solid if generally predictable and melodramatic “bad things come to those who vacation” thriller.

“Weekend” is a Leighton Meester star vehicle based on Sarah Alderson’s scripted adaptation of her novel. Our “Gossip Girl” veteran plays an American expat unhappily-married and living in London, a new mother who could use a few days off.

Her just-divorced hellcat pal Kate (Christina Wolfe) thus summons Beth to a Croatian getaway. A little girl-bonding, sight-seeing and dressing up to paint the town red…or as red as Beth, who is still breast-feeding, will allow. But Kate, determined to “find the limit” on her ex’s credit card, won’t hear of it.

One black-out blur of a night later, Beth wakes up to find Kate missing, blood on the floor, Kate’s locked phone left behind and Croatian cops (Amar Bukvic, Iva Mihalić) who’re 50 Shades Disinterested in this “case.”

Beth has to put off the husband back home (Luke Norris), ignore “that’s just like Kate” cracks from her friend’s ex (Parth Thakerar) and the dismissals of the cops, and rely on the Syrian refugee taxi driver (Ziad Bakri) who picked her up at the airport to help her retrace that night and what might have happened to “my best friend.”

The plot serves up a smorgasbord of possibilities and suspects — exes and “escorts,” creeper hotelier and entirely-too-careless cop. Meester isn’t particularly good at selling the “Maybe Beth did it” angle, thanks to the heat of the “I could never DO that” protests she manages.

Our leading lady summons up just enough paranoia to pull off a convincing breakdown under grief, despair and dismay.

But too much of “The Weekend Away” plays like a walk-through before the AD actually yells “ACTION.” The chases, fights and get-aways have a half-speed quality, as if everybody’s scared of getting hurt or working up too much of a sweat before Take Two.

This is most obvious in Meester, whose Beth doesn’t show the strain or effort it would take to get away here or to entrap a “suspect” there.

She’s always made a likeable if somewhat low-heat lead, and she leans a little too hard into this “exhausted new mom” back story to let this movie get up to speed and give us a sense of rising stakes.

The plot works its way past red herrings and into anti-climaxes, never quite drowning in melodrama, but coming damned close, time and again.

That makes for a “Weekend” that gets away from one and all, rather than delivering the roundhouse punch surprises the genre cries out for and the formula demands.

Rating: TV-MA, violence, drugs

Cast: Leighton Meester, Christina Wolfe, Ziad Bakri, Amar Bukvic, Iva Mihalić and Luke Norris

Credits: Directed by Kim Farrant, scripted by Sarah Alderson, based on her novel. A Netflix release.

Running time: 1:31