Gabriel: “The pace wavers between gun-the-engine melodrama and high-toned apercus.”

Did the angel Gabriel flutter down from heaven to save Guernsey islanders from German occupation in 1943? Or did another Gabriel wash ashore, naked, from a shipwreck? He doesn’t know. He has amnesia, and Gabriel isn’t his real name. So who is he, and which side is he on? He could be British, since he speaks perfect English. But then again, he also speaks letter-perfect German.

Due to their extreme situation, just about everyone in Moira Buffini’s melodramatic thriller Gabriel is two people. On June 30, 1940, the Germans invaded the Channel Islands. At first, they were civil. But as the war continued, they used harsher tactics. They put 4000 locals in work camps, evicted people from their homes, and occupied the churches, draping a German flag over the altars. They banned radios, patriotic songs, and V-for-victory signs. As food and fuel became scarcer, islanders resorted to black market tactics. If perpetrators were caught, soldiers beat them with rubber hoses.

So islanders have two identities: who they are, and who they must be for the invaders — Jeanne Becquet most of all. After German officers occupied her home, the Hermitage, she moved her family into a rickety wooden farmhouse. Although “marooned in a house full of bitches,” she will do anything to protect her kin: pander to the Nazis, even if that means an affair with an officer. Iron tough, she’s also a key player in the black market. In effect, she’s the British Mother Courage.

Enter Major Von Pfunz. Large, beady eyes glinting behind dinky round glasses, hair in a bowl cut, he’s oddly amused by his surroundings, as if miscast as an officer. Jeanne assumes he doesn’t speak English, so she drops her chipper mask and cuts loose. His name sounds like “flatulence,” she says. Some Germans are handsome, but most “look like goblins.” To which the Major replies, “Nice, thank you.”

She's tipped her hand. So why doesn’t Von Pfunz arrest her on the spot? Aside from stealing drama from the play, the revelation creates a taut dynamic: he knows her secret, but, although he seems almost caring, does he have one too? And will he use her to expose other family masks?

Jeanne’s 10-year-old daughter, Estelle, haunts their former home, stealing this and re-arranging that, like a preteen poltergeist. Her fun could cost her life. Lily’s heritage could cost Lily’s. She’s Jewish.

Gabriel has the makings of a teeth-gnashing, page-flipping potboiler. But the playwright packs its long two acts with what a tech-writer friend of mine calls “significant language” – every so often it waxes literary; the harassed islanders become poets. The pace wavers between gun-the-engine melodrama and high-toned apercus. The play itself has two identities.

They collide in Estelle’s “square of power,” drawn in chalk on the living room floor. Estelle wants to bring her brother back from the war. Instead, she thinks she’s conjured the unconscious, naked man (who would have frozen to death on the shore were the play more realistic). She calls him “Gabriel,” as in the archangel. Though married to a pilot, Lily falls for the mysterious stranger, no matter who he’ll turn out to be.

The play may ping-pong, but the North Coast Rep’s first-rate production keeps its theatrical compass due north. Marty Burnett’s set is all rustic slats (forming a V in the center) and hardscrabble furnishings. One can imagine the family’s Hermitage by comparison, and by Jeanne’s resplendent, red outfits (costumes by Elisa Benzoni). Matt Novotny’s lights add a sense of claustrophobia to the scene, and Ryan Ford’s sounds suggest rampant Channel Island winds.

Credit director Christopher Williams for a fluid ensemble cast. Often when a pre-teen’s on stage, one tends to overlook a few faux pas. Young Catalina Zelles is the opposite. She’s on target as the eerie Estelle.

Lilli Passero and Anabella Price bookend the piece as withdrawn Lily and disgruntled Lake (back in the '80s, Price was in Stephen Metcalfe’s Strange Snow at the Old Globe — a play that’s more relevant today). Gabriel’s a Black Box, more a symbol than a character (as in, “Hi. I’m mysterious”). Alan Littlehales provides substance where he can.

Gabriel’s an ensemble show, but it has two stars. Jessica John and Richard Baird excel as Jeanne and Von Pfunz. Jeanne’s world is upside down. John is fierce to the bone. A many-sided warrior, she layers words with lies so well they almost seem true.

Baird gives such a modulated performance, one almost wants to believe Von Pfunz is the ultimate oxymoron: a nice Nazi. He seems soft, even delicate, a fragile smeller of flowers. But he has two identities. Baird unpeels him like an onion, slowly revealing a heart encased in evil. The play may meander here and there, but these performances make it a must see.

• Gabriel, by Moira Buffini.
• North Coast Repertory Theatre, 987D Lomas Santa Fe Drive, Solana Beach.
• Directed by Christopher Williams, cast: Richard Baird, Jessica John, Alan Littlehales, Lilli Passero, Annabella Price, Catalina Zelles; scenic design, Marty Burnett,, costumes, Elisa Benzoni, lighting, Matt Novotny, sound, Ryan Ford, hair and wigs, Peter Herman.
• Playing through March 17; Sunday and Wednesday at 7:00 pm. Thursday through Saturday at 8:00 pm. Matinee Saturday and Sunday at 2:00 pm.