Intending to marry Cynthia (Anne Helm), Jay Menlow (Robert Morse) is stranded at the alter on the day of the blessed occasion. Left with a paid Honeymoon vacation in the Caribbean, Jay takes along best man Ross Kingsley (Robert Goulet) to the Boca Boca, a "honeymooners only" resort. Ross soon finds an attractive companion in the resort's social director, Lynn Hope (Nancy Kwan). Jay, on the other hand, shows signs of weakening to Cynthia's telephone apologies and Ross desperately attempts to prevent their reconciliation so he may continue to enjoy the arrangement. When Ross' employer Mr. Sampson (Keenan Wynn) arrives on the scene with his blank-headed mistress, Sherry (Jill St. John), things begin to get a bit crazy. Shortly thereafter, Mr. Sampson's wife (Elvia Allman) arrives looking for her philandering husband. Finally Cynthia appears on the frantic scene to ensure chaos in the proceedings.