Alex Carson is in mid-life freefall. He owes a quarter million in back taxes, his bipolar wife Connie keeps going off her meds, and his dog's just died. When his estranged twin brother Dave, a multi-millionaire with a disease that's reduced him to crutches, invites him for a weekend visit, Alex is so eager to escape his own reality that he accepts, even though his wife decides at the last minute to tag along.
Over drinks that evening, Dave tells them he suspects his wife Kristina of having an affair. Uninterested in Dave's marital problems, Connie seeks sympathy for Alex's tax debt and asks for a loan, which Dave refuses. In a fit of anger, Connie knocks Dave down a flight of stairs and accidentally kills him.
Given their motive and opportunity, Alex and Connie fear a murder charge if they inform the police, so he decides to take Dave's place long enough for her to return home and establish an alibi. In a few days, he'll engineer Dave's "death" all over again, and escape to rejoin her. Although she suspects he just wants to sleep with Dave's wife Kristina, she's forced to go along with the plan.