No longer weighted down by the perukes she had to wear in The Duchess, Keira Knightley returns to the simpler chignons of Atonement in another World War II-set prestige piece with a starchy literary pedigree-this one scripted by her mum, Sharman MacDonald. Knightley sings and affects a Welsh whisper as Vera, a childhood friend of Dylan Thomas (Matthew Rhys, the gay sib on Brothers and Sisters), who meets up with the pickled poet in London during the Blitz. When Thomas’s even more aggro spouse, Caitlin (Sienna Miller, in a role originally attached to Lindsay Lohan), arrives, Vera opens her flat to the couple, and the trio becomes one big cuddle-puddle. Adding a fourth wheel, Vera hastily marries stoic soldier William (Cillian Murphy); while he’s fighting in Greece, the threesome decamp to adjoining cottages in Wales. Director John Maybury showed a defter hand with the artist biopic in his 1998 Francis Bacon film, Love Is the Devil. Here, he repeatedly falls into the genre’s traps, creating an inert, claustrophobic movie in which the constant sound of inhaled cigarette smoke is as showboaty as Rhys murmuring Thomas’s poetry and Murphy’s shell-shock. Occasionally, Angelo Badalamenti’s fine score will pleasantly remind you of Mulholland Drive. Knightley and Miller’s pseudo-sapphic tub-splashing will not.