Writer-director Tom McCarthy, whose previous two features were The Station Agent and The Visitor, is clearly drawn to the seriocomic. Thing is, his light, nimble way with character and attention to offbeat detail serve the -comic aspect much more effectively than the serio-. For a long time, McCarthy’s Win Win barely has a discernible narrative, and yet it’s an utterly charming (if somewhat shambling) tale of a financially desperate attorney and high-school wrestling coach (Paul Giamatti) who winds up quasi-adopting the teenage grandson (newcomer Alex Shaffer, fantastically affectless) of a client (Burt Young) in the early stages of dementia. But when the kid’s horrible mom (Melanie Lynskey) turns up from rehab to reclaim him, the film takes an ill-conceived nosedive into unconvincing melodrama. Still, it’s worth seeing for the relaxed camaraderie among the fine ensemble cast, and for such delectably realistic, out-of-nowhere moments as a conversation that gets interrupted by someone noticing Wii Golf.