If you shoved "Rosemary's Baby", "Little Shop of Horrors", and "Fatal Attraction" into an atom smasher, the result might come out looking something like Erin Mallon's new play, "Branched", now playing at the HERE Arts Center.  New Age yuppies Tamara (Tara Westwind) and Martin (Andrew Blair) live in a world of Ikea shelving units and aqua silverware with their son, Ben (Michelle David in a Prince Valiant wig), and new arrival Beatrice. Beatrice is, incidentally, a tree; maybe this has something to do with the paleo diet Tamara follows and foists on the rest of the family. (We get to witness a moment of Tiger Mother rage when Tamara takes a meeting with Ben's new teacher, Belinda -- played by a bubbly-if-manic Marguerite Stimpson -- after another child shares his cheerios with him.)

Belinda, as it turns out, moonlights as a real estate aspirant and home wrecker. She starts a love affair with Martin -- and damn if the play doesn't lose all direction from there. The plot becomes so tangled up in the affair and the pseudo-incestuous and subversive-to-no-clear-end rituals of the family (pre-meal Underwear Invocations, scheduled sex sessions, violin practice and hypnopaedic Tony Robbins listenings in utero) that we almost forget about the branch-festooned BabyBjorn (or, if you like, confused metaphor) the players each have turns hauling around.

Director Robert Ross Parker of Vampire Cowboys has his ensemble playing the schtick to the cheap seats; Kristina Makowski's costumes offer a bright palette to match lighting and scenic designer Nick Francone's cyan-splashed set; and it's all scored by sound designer Shane Retting's sampling of Baroque era earworms (Vivaldi et al.). Combined with the invisible entrees the characters "ingest" (as Tamara would say), these elements give us the feeling of witnessing some demented game of playing house.

In the end, we are able to see the intent -- the cornered child in limbo rejecting, at last, the vices and foibles of his guardians. But the ending, when it comes, doesn't feel earned. Neither does the tree baby.