My Best Friend's Wedding (1997) - Synopsis

Nine years ago, Julianne Potter and Michael O'Neal, lovers, made the transition to just being friends. Best friends. They made an agreement that if neither were married by the time they were 28, they would marry each other. Well, Michael has asked the big question… to someone else.

Julianne, under Michael's invitation, goes to Chicago to both be with him during his time of need and also to be the Maid of Honor of his bride, Kimmy Wallace, the wealthy daughter of the owner of the Chicago White Sox. Jealous of Michael's perfect fiancée, she sets out to ruin their relationship and win him back for herself.