Richard Field is a successful businessman who has become romantically involved with younger employee Diane Lovering, but he is unable to persuade his grasping wife to grant him a divorce out of his dysfunctional marriage. Diane meets dashing rancher Mike Bradley through his wise-cracking pal Johnnie on a South American ocean voyage, and they begin a shipboard romance that carries over to his Argentinian ranch. Diane decides to return to New York and tell Richard in person that she intends to marry Mike Bradley. When Diane gets there Richard surprises her with a wedding ring and the morning newspaper citing Mrs. Field is in Reno obtaining a divorce. Richard had to agree not only to a large monetary settlement but was forbidden to see his sons. Diane didn't have the heart to tell Richard about Mike and decides to marry him. Diane writes a "Dear John letter" to Mike explaining a calculated mercenary decision that she prefers the position and financial status that Field's can offer her over the love that Mike can. However, is she meant to be Mrs. Field or Mrs. Bradley?