Maid of honor Sam organizes a bachelorette party in
Paris for her childhood best friend Betsy. Unbeknownst to the others, Sam is a secret agent, having arranged the trip to intercept a rogue
bioweapon, but her disappearance from the party leads Betsy to drunkenly name her fiancé's sister Virginia as maid of honor instead. Sam's handler Nadine urges her to attend the wedding anyway, and she arrives in
Savannah, Georgia for the festivities, meeting Betsy's fiancé Ryan Caldwell and his wealthy family at their private island estate. Ostracized from the bridal party, Sam flirts with the best man Chris, much to Virginia's jealousy. Before the ceremony begins, Sam's attempt to comfort Betsy backfires, and she slips away after Betsy suggests they have grown apart as friends. The wedding is taken hostage by a team of mercenaries led by Kurt, who demands access to the Caldwells' vault, which is keyed to the family's wedding rings. Ryan is shot in the leg when it is revealed that Chris, the son of the Caldwells' jailed former business partner, is in league with Kurt. Sam evades capture, subduing several mercenaries and Chris before being assumed dead, but Betsy spots her fighting her way to the kitchen. Convincing Kurt to let her find food for the hostages, Betsy reunites with Sam, who has taken Ryan's ring from Chris. Betsy returns to the hostages and they overpower the guards, escaping through the house's secret passages to a nearby train depot, while Sam creates a distraction and is captured. Unlocking the vault, the mercenaries steal a fortune in gold bars and an incriminating hard drive, which Chris believes will exonerate his father. Before Kurt can execute them, Sam flees with Chris to the family's distillery, where the mercenaries leave them to boil alive inside a whiskey
still, but the bridal party returns to rescue them. Firing on the mercenaries with the estate's antique cannon, Sam and Betsy give chase across the grounds in a
hovercraft, pursued by Chris. Sam fights off the mercenaries and throws Kurt overboard, while Chris demands the hard drive at gunpoint, but Sam and Betsy jump to safety as he crashes in a fiery explosion. Having realized Sam was in danger, Nadine arrives with a rescue team, capturing Kurt and his men. At the train depot, Betsy marries Ryan in an impromptu ceremony, but they are interrupted by a badly burned Chris, who has Kurt's detonator for explosives planted throughout the house. He is disarmed by a sympathetic Sam, who explains that the hard drive proves his father was working for the mercenaries' criminal employers. Catching the
wedding bouquet, Sam accidentally hits the detonator, destroying the Caldwell mansion. Virginia returns the maid of honor role to Sam, who makes a heartfelt toast to Betsy and their friendship, and swears the party to secrecy about her life as a secret agent. ==Cast==