On the frontlines of the battle of the bulge, otherwise known as trying on bathing suits in the communal dressing room at Loehmann's, freelance writer Jaine Austen makes a new friend - a wannabe actress named Pam - and gets a new job: sprucing up Pam's bare-bones resume. Their feeling of connection is mutual, so Pam invites Jaine to join The PMS Club - a women's support group that meets once a week over guacamole and margaritas.

But joining the club proves to be more a curse than a blessing for Jaine. Though she is warned that Rochelle, the hostess, makes a guacamole to die for, Jaine never takes the warning literally. Until another PMS member, Marybeth, drops dead over a mouthful of the green stuff. Now instead of dishing dirt with The PMS Club, Jaine has to dig up the dirt on the surviving members....