Thanks to its understated elegance and surpassing central performance, this modest, too-eagerly schematic period drama is more engrossing than it has a right to be. The latest gloss on the gently condescending retro-modernist missionary genre—in which an urbane hero preaches the good news of progress but runs flush up against a wall of reactionary rural backwardness—Stella Days takes place in 1956, when electrification was finally brought to the boggy Irish boonies. A Rome-educated, American-acculturated intellectual, Father Daniel Barry (Martin Sheen), tries to enlighten his parish in both literal and cultural ways—most brazenly via a passion plot to open a town cinematheque—but is opposed at every turn by Brendan (Stephen Rea), a fearmongering isolationist with political aspirations. Too many subplots and binary conflicts crowd the narrative (all cleanly on point about the dark-versus-light theme), but director Thaddeus O’Sullivan puts it over with a gentle hand, and most importantly, establishes an appropriately ruminative tone for Sheen’s embattled, bottled intensity. One of the most shamefully underused talents Hollywood has ever produced, Sheen gets a rare shot at captaining a film here, and he turns this wee cozy yarn into something significantly felt. Behind a mask of unsettled benevolence, and through those fierce Sheen eyes, his inescapably lonely priest glares at the world with an apt mix of fervor and disgust, hope and despair.