Sadly, the ad campaign for filmmaker Chris Kentis’ Open Water would give the impression that here is another Jaws clone to frighten audiences with monsters, razor teeth in rows and bloody shredded limbs. Freebie PR notepads even sport missing shark-bite corners. On the History Channel or Discovery (mentioned, humorously, in the film), trailers for Open Water pop into re-creations of fatal shark attacks in Hawaii or of an underwater photographer lost at sea who, ten years later, revisits her Galapagos mishap.

Nothing could be further from the truth of this modest-budget work. Done in spare time with a crew of four (the director, producer-wife Laura Lau and her sister Estelle, plus a boat captain) and no special effects or computer-generated images, the result is not so scary as our anticipations nor, in the strict sense, a thriller. Here are deeper things in mind: the fragility of life, its closeness to death; the hurly-burly of techno-existence as against love and relationship; and individual man’s place in a Great Chain of Being at once beautiful, awesome and terrifying.

After burial alive, in coffins or caves, our greatest fear is probably water. Most would prefer to risk a desert, at least terra firma. “Based on true events” (like practically everything nowadays), this story grew out of dive-magazine reports of rare but documented incidents involving divers stranded in mid-ocean. Not wishing to particularize and intrude on any individual’s trauma or spa’s tourism, Kentis developed his script with no precise setting.

Because single-character movies are almost unthinkable -- even Tom Hanks needs a companion/confidant, if only Wilson the volleyball -- the straightforward plot involves suburban couple Susan (Blanchard Ryan) and Daniel (Daniel Travis), so multi-task obsessive they communicate by cell phone from driveway to house and can scarcely find time to plan, let alone take, a vacation breather. Rushed and off to the Islands, too mentally weary to make tropical love, the attractive, winning pair ups bright and early to join a 6:30 am party of twenty for an ocean scuba run. Neither the dive-master (Michael E. Williamson) nor his assistant (John Charles) and pilot (Cristina Zenarro) are developed, nor, beyond a brief pushy New Yorker, are the other eighteen so much as named or differentiated.

When a tally count is mishandled following the dive, the boat sails off without late returnees Daniel and Susan, who bob up to find themselves alone. Passing fishing or pleasure craft and a tanker seem near yet so proverbially far, the head view from the surface is limited by swells and wavelets, and they float in place, awaiting rescue. With the two, a third character is Nature, the creatures below -- for once not ooh! ah! overdone -- and a beautiful, indifferent sky and sea surface, the latter particularly well observed by the camera.

Slight but noticeable natural changes indicate time’s passing, so the (increasingly common) device of titles to set the clock is unnecessary, as the couple talk, bicker, are contrite and make up, reassure one another, grow closer. Nature calls, thirst and hunger intrude, the woman’s Dramamine wears off to nausea, sea life visits. Fright and panic arise to alternate with calm, while primal fear surges from the brainstem.

Desperately seeking publicity, some films ask that their endings not be told. A fig for them; but Open Water is so good that, beyond revealing that next morning the couple’s unclaimed gear is discovered, compliance will be observed in this case. See the film, not for special effects or jump-out-in-your-face scares, but for a sharply recorded and realized picture of what lurks beneath our surface. 

(Released by Lions Gate Films and rated "R" for language and some nudity.)