Slight, dark, daft and right on the edge of “twee,” “Say My Name” takes a demand uttered in a moment of passion, an unusual setting and a long night of missed communications, misunderstandings, unlikely escapes and violence and turns it into something funny, something almost romantic.

It’s set on an island off the coast of Wales, South Mouse, reachable only by ferry.

That’s where Mary (Lisa Brenner) and Statton (Nick Blood) are going at it, hot and heavy. That’s when she hits him with that deal-breaker bit of sex talk in a one-night-stand.

“Say my name!”

He hems. He haws. He’s um, busy.

“I just need to hear your ACCENT!”

He doesn’t have it. He tries, but in the heat of the moment…

Mary’s outrage spills over into pop psychology, Statton’s defense gets into the mnemonic devices he uses to recall names. It goes from bad to awkward.

“So you were TESTING me during sex? That’s entrapment! Sort of.”

They barely have time to disentangle from her outrage, when two armed goons — played by Mark Bonnar and Celyn Jones — bust into their room at the scenic Royal Grand Hotel. South Wales.

“We like shiny stuff!”

Statton cowers. Mary? She takes it in stride.

“Can I get dressed?”

“D’ye HAVE to?”

The robbers bicker, a gun goes off. Somebody is hurt. Somebody is the island’s last piano tuner. Somebody once aspired to be an opera singer.

“Don’t stereotype ME, mate!”

SOMEbody used to be a nun, and her “real” name isn’t Mary.

“You wanted him to call you by your ‘nun’ name during sex?”

And thus the night begins, with tables-turned and turned-back-again, cops, paramedics, “The Pirates of Penzance,” a “nurse,” a club, a church at dawn that’s the “House of the Rising Sun,” and a jail cell.

The banter — the script is by Deborah Frances-White — is quite often quite witty.

“Are you a chartered MORON? THIS is why you’re the sidekick!”

The story leans on winning anecdotes — Statton’s failed marriage, Mary’s odd journey from America to Wales, the robber’s opera singing ambitions.

The structure’s a bit stodgy — chapters. “I. At the Hotel with Mary…II. In the Lockup with Carol.”

But director Jay Stern and the cast keep this featherweight-with-firearms farce on its feet, skipping along if not actually galloping.

Brenner, a screen veteran with mostly bit-part credits, makes Mary/Carol etc. a font of surprises and world-weariness. Blood’s Statton may be mousey and rattled, shocked at what’s going on, but Breener gives her character an antsy, angry “What fresh hell is this?” attitude.

Statton makes a fine go of being “mild mannered” enough to pass for a piano tuner. His character is the one that makes a journey, to somebody braver and more assertive.

Bonnar has a hint of Robert Carlyle’s “Trainspotting” rage, and Jones plays a plump, sensitive Nick Frost lite here. Amusingly.

As the story scampers about, everybody has something funny to say or play. Peter Davison’s a lawyer with no real interest in “getting involved,” a club goer has a ready-made pick-up line for Mary.

“Wanna Brexit? Come back to my place?”

It’s so slight and silly that when it hits you with some real heart in the third act, that may be the biggest surprise in this comedy of surprises, twists and moments of faint, feigned shock.

“It’s all kind of funny when you think about it.”

Indeed it is.

MPAA Rating: R for language throughout and some sexual content.

Cast: Lisa Brenner, Nick Blood, Celyn Jones, Mark Bonnar

Credits: Directed by Jay Stern, script by Deborah Frances-White. Am Electric Entertainment release.

Running time: 1:23