NEW YORK — Out in the dusky backyard, a little boy named Ira is camping solo in a canvas tent. Inside, his parents, Bev and Morty, are down in the brand-new basement rec room, hosting an impromptu party and serving fruit-festooned cocktails from their well-stocked bar. It’s 1950-something in a Chicago suburb, and beneath the determinedly cheery surface lurks an ominous alienation.

This is “Blood Play,” a somewhat enigmatic dark comedy from the Debate Society. The Brooklyn, N.Y.-based theater company is bringing the piece, its seventh full-length play, to ArtsEmerson’s The Next Thing Festival for three performances Feb. 21-23.