Rebecca Hall is Hannah, widow of rock star Hunter Miles, who made “a single, nearly perfect album” of soulful acoustic folk before he died suddenly several years back. Jason Sudeikis is Andrew, a university professor who deems Hunter’s work “timeless” and wants to include the singer in the book he’s writing about tragic great American musicians. Hannah is reluctant to help Andrew with his research for lots of reasons: the most important one is the one she is unable to admit to herself, that she does not want to move on with her life. Does her finally agreeing to work with Andrew mean that she is, perhaps, ready to take her first tentative step away from grief? Tumbledown is the first feature from director Sean Mewshaw (who wrote the script with first-time screenwriter Desiree Van Til), and it borrows the conventions of romantic comedies to craft a nicely observed portrait of the pain of letting go of the past and of opening up to new possibilities of friendship and romance. There may not be a lot of passion in the inevitable coming together of Hannah and Andrew, but there is some pleasant zing in their banter as they trade genial culture-clash barbs; he’s from New York City; she loves the rural quietude of the mountains of Maine, where most of the film takes place. (The film was shot in Massachusetts, which looks warm and inviting; the bit of small-town kook that Mewshaw indulges in feels authentic, not forced.) The impressive cast also features Blythe Danner (The Lucky One) and Richard Masur as Hannah’s parents, Griffin Dunne (Dallas Buyers Club) as her bookstore-owning pal, and Joe Manganiello (Magic Mike XXL) as her occasional fuck-buddy. But Hall (The Gift) and Sudeikis (Horrible Bosses 2) are why this works as well as it does: she is achingly expressive as her Hannah walks a rocky emotional path, and he is once again charming and genuine as a realistic grownup man who is much more appealing — and actually much funnier, too — than the goofy-comedy punching bags he has built his career on.