Here's a brief synopsis of the film written and directed by Leslye Headland:
Regan is used to being first at everything. Imagine her horror and chagrin when she finds out the girl everyone called Pig Face in high school is going to tie the knot before she does! But Regan sucks it up and takes on bridesmaid duties along with her childhood pals: substance-abusing, promiscuous Gena and ditzy Katie. The single ladies are determined to put their bitterness aside and have an awesomely hedonistic bachelorette party. Armed with acerbic wit and seemingly endless supplies of coke and booze, the foul-mouthed femmes embark on one very long and emotional night filled with major wedding-dress panic, various bodily fluids, and cute ex-boyfriends.The film has an impressive cast, too, starring Kirsten Dunst, Isla Fisher, Lizzy Caplan, James Marsden, Adam Scott, and Kyle Bornheimer.