Two motherless sisters, with a history of conflict, break off relations when the promiscuous and more irresponsible of them sleeps with her sibling's boyfriend, but they eventually reconcile with the help of a grandmother they never knew they had.
Flirty, flaky party girl Maggie (Cameron Diaz) and plain, dependable lawyer Rose (Toni Collette) are sisters, best friends and bitter rivals who seem to have nothing in common but size 8 1/2 feet and some family secrets. After a heart-rending falling out, they accidentally discover they also share a long-lost grandmother (Shirley MacLaine). Together they travel a bumpy road toward making peace with each other and themselves.