I might be out of touch but I only vaguely remember hearing about this movie. I've never seen another Rebel Wilson movie but I thought that this one was kind of a waste of her comedic genius. She was the least funny of all the characters.
Rebel plays Becky, one of four girls who went to school together, the others played by Lizzy Caplan, Kirsten Dunst and Isla Fisher. First let me say that while I love the other two, I really haven't liked anything Kirsten has done since I was a teen and obsessed with crazy/beautiful. I have to say she looked amazing in this, really grown up and without the stringy/dirty hair. I digress...
Becky tells Regan (Dunst) that she's getting married. Secretly Regan is pissed because the fat friend is the first to get married in the group. Regan is very Type-A and has her wedding planned out even though she's more about her career than her man.
She tells Gena (Caplan) and Katie (Fisher) and they all go for the wedding weekend. Lizzy and Isla are hilarious as basically oversize children who love to party and have never grown up. They're intent on throwing Becky a bachelorette weekend even though she has outgrown that lifestyle. When Gena brings cocaine, Katie, in her excitement yells out "you brought cocaine" in the middle of the hotel lobby. That was hilarious.
Anyway, you see through out the hijinks (including ruining the wedding dress when Katie and Regan both climb in it to prove that Becky is ginormous) Regan learns to relax a little and Gena and Katie learn to grow up. They don't come out perfect but they realize a lot about themselves when they see Becky all grown up.
Beware that this movie is not for the close minded as they do a lot of drugs/drinking and talk about hookups and abortions a lot. I liked this because it was relatable even though I do not do these things many people my age do. The guys were pretty funny too.