It's rare that a mediocre movie survives because the cast proves endearing. That may be the case with Boundaries, a story about an aging and very conniving father (Christopher Plummer) who tries to reconcile with his grown daughter (Vera Farmiga). Director Shana Feste quickly turns Boundaries into a road movie in which Plummer's Jack, a character who has been expelled from an assisted living facility for growing marijuana on the premises, rides from Oregon to California with his daughter. Farmiga's Laura wants her recently evicted father to move in with his other daughter (Kristen Schall), a ditzy woman who lives in California. Also along for the ride: Laura's son (Lewis MacDougall), a high-school kid who receives lessons in creative irresponsibility from his grandfather. Bobby Cannavale turns up briefly as Laura's ex-husband, a man who -- like his former father-in-law -- seems to be involved in the pot trade. Other stops include a meeting with old pals to whom Plummer previously sold pot or engaged in other dubious activity (Christopher Lloyd and Peter Fonda). Predictable and never totally convincing, Boundaries nonetheless features a fine performance by Plummer, who pours on the roguish charm. Little about the screenplay proves memorable, but Plummer, who's ably supported by the rest of the cast, makes this road trip tolerable.