Over three years in the 1960s, seven star-stuffed Beach Party frolics portrayed mild “wild” teens who turned out to be pretty good kids, after all. Beach resort Drama/Mex, from writer/director Gerardo Naranjo, is foul-mouthed in its dialogue, more specific about its sex but not very graphic, and devoid of any causal relationships.

Blurbs on the Mexican’s second feature praise its gritty verité and purposeful ambiguity. But a largely inexperienced cast, underlit night or overexposed daytime handheld video shooting (by Tobias Datum), insufficient pre-story exposition and end-story resolution, should not be confused with good filmmaking. With so much occurring after sundown, and such shallow depth of field technique, the announced “same long, hot day” doesn’t seem true, either, although in desperation that time (and location) limit is as good as anything else served up with which to link “two interlaced stories.”

Not now or subsequently is the slightest hint breathed as to why company executive Jaime (the sole veteran, Fernando Becerril) signs for the cash payroll envelope in advance, spits conspicuously on the boss’ desk in front of that superior, drives home in the evening to his two high school children and sexually rejected wife, and early next morning takes a room in a nondescript beachfront cabana motel.

Parallel to this, or simply at about the same time, sexually active teen Fernanda/”Fer” (a début feature for Diana García) verbally laces into her recent ex-flame Chano (Emilio Valdés) and taunts him so mercilessly with her current one, gangly Gonzalo/”Gonzo” (Juan Pablo Cantañeda, another first-timer), that he climbs an outside wall, over the roof, and forces her on the living room floor. For the time being, she seems to be living alone in the sumptuous gardened place, her mother God knows where and father moved into an office in one of the high-end hotels he owns. Chano pockets what he can, while the girl and he halfway plot an escape, necessary because her father is after the young man for previous theft.

Meanwhile, young babyfat adolescent Jennifer (Miriana Moro) has run away from Mexico City to be hidden by her aunt but winds up being instructed by three others her age about how to become one of them, the Yahairas. Lolitas with lollypops and cheap outsized sunglasses, they use their little English to pick up older gringos on the beach and, without going so far as full service, coax small favors from them. Styling herself Tigrillo, “Little Tiger,” Jenny sneaks in and makes off with Jaime’s wallet while he unsuccessfully holds a revolver to his head.

Moved by the bespectacled middle-aged man’s agony, she basically forces her presence on him and later returns the billfold while the two of them do one or two kids’ hotspots, where he shyly warms up but is still glaringly out of place and refuses to let her spend the night in his room. Presumably that same night, a drunk Gonzo scours the usual hangouts for Fer, because three friends have interrupted his soccer goalkeeping and drinking to report seeing her and Chano in a kissing clinch.

To unfocused background neon -- and often an out-of-focus everything -- the night wears on, building to nothing in this Acapulco once, but no longer, the jet-set latest thing but now home to mortally unhappy adults and the bored young people to whom it is “Crapapulco.”

Unfortunately, Drama/Mex fails to supply motivation for or roundness to its unappealing inhabitants, and its two stories lack any reflection to one another. The film neither engages an audience nor informs it.

(Released by IFC Films; not rated by MPAA.)