David Farr takes the giddy, heady days of early motherhood—the frustration and isolation, the exhaustion and confusion—and mines them for creepy, paranoid thrills in “The Ones Below.”

Would you let this hyper-maternal, grief-stricken woman babysit your newborn?

The Ones Below is an intimately disturbing nightmare of the upper middle classes, with tinges of melodrama and staginess, entirely appropriate for its air of suppressed psychosis.