Noah (Dax Shepard) has just gotten fired, faces pressure from his wife (Liv Tyler) to have a baby, and must contend with her socially inept cousin (Mike White), who wants to stay with them for a few days while he finishes his screenplay. That’s when Marilyn (Diane Keaton), Noah’s high-maintenance mother, announces that she’s moving in, turning Noah’s bad day into a presumably hilarious and awful one. Directed and co-written by Vince Di Meglio, Smother aspires to an edgy style of non sequitur humor in which the situations aren’t particularly funny or original, but do allow room enough for throwaway jokes and bizarre running gags. The problem with this flimsy narrative approach is that the film’s laugh quotient depends entirely on whatever the cast can bring to this tired setup. In that regard, Smother is fortunate: Shepard is dependably low-key, White goes a long way with his creepy-smile stare, and Keaton demonstrates boundless charm when she isn’t restrained by the clichés of her nagging, needy character. Still, with its mixture of high-profile talent and low-watt comic inspiration, Smother feels like the sort of misbegotten curiosity that Comedy Central uses to fill its Sunday-afternoon programming. And considering how quietly Smother’s distributor dumped it into theaters, expect to see it there soon.