A couple divorces by mistake during a madcap Mexican vacation.

Valerie Edwards, wife of advertising executive Dan Edwards, goes to lawyer Shad Nathan for a divorce on grounds of boredom after 19 years of marriage and two children, Tracy and David. On the advice of his business partner and closest friend, Ernie Brewer, Dan takes Valerie to Mexico for a second honeymoon. They stay at Miguel Santos' hotel and discover that they really want to remain married, but through a mixup Santos gets them a Mexican divorce. Dan returns to the States to take care of urgent business and sends Ernie to Mexico to tell Valerie that arrangements for their remarriage are being made. Through another mistake by Santos, Ernie and Valerie are married; and Valerie decides to teach Dan a lesson by not divorcing Ernie immediately. Ernie, a sophisticated bachelor, tries to adapt to the life of a family man, while Dan moves into Ernie's apartment and leads a carefree bachelor's existence. Life continues in this manner for a short while, but all concerned recognize the unsuitability of affairs; on Thanksgiving Day, Dan and Valerie resume their marital relationship. Valerie soon tells Dan that she is expecting another child.