As an affluent New England family prepares for one daughter’s wedding, another named Kym (Anne Hathaway) — just out of her latest stint in rehab — whirls into town causing upheaval. The sister, Rachel (Rosemarie DeWitt), is more than a bit resentful of Kym’s antics taking center stage, and as time ticks by, long-simmering family tensions come boiling to the surface.