Beleaguered Philip Davis is sent at his father's behest to place his eccentric grandmother, Estelle, into an assisted living facility. To add to his troubles, his small-time drug dealer sister Megan decides to join him, using the trip as a cover for a large marijuana buy.

When Estelle discovers her grandson's plan, she furiously takes off for Seattle, unaware that her granddaughter's drug haul is stashed in the trunk of the car. The estranged siblings have no choice but to go on the road after their wayward grandmother, the taxidermied dog she keeps as a companion, and five pounds of marijuana.