Barney Mason (Robert Reed) and his ex-wife Terry Larsen (Loretta Swit) meet on the cruise with their new partners (Pamela Bellwood and Richard Mulligan); Julie's (Lauren Tewes) love interest Jim Wright's (Charles Frank) chaperoning of senior citizens leaves little time for them to be together; teenagers Graham (Scott Baio) and Kelly (Kristy McNichol) find puppy love, together.
Tennis pro Maureen Mitchell (Brenda Benet) runs into sportswriter John Ballard (Bill Bixby), who defamed her in his column. Cyril Wolfe (Milton Berle) annoys his wife Anita (Audra Lindley) and fellow passengers (Lynn Adams and Britt Leach) with constant practical jokes. Mexican April Lopez (Charo) stows away in a laundry hamper.
Isaac's (Ted Lange) favorite singer, Roxy Blue (Diahann Carroll), becomes his lover. Talky Robert Tanner's (Jim Nabors) popularity increases when fellow passengers think he may be a jewel thief. Bert Fredericks (David Groh) plans his wife Denise's (Michele Lee) birthday party, but she thinks it's a murder plot.
Stories include: a reprobate steward (Bob Crane), cute honeymooners (Kathy Bates, John Rubinstein), and a financially strapped supermarket cashier (Bruce Solomon) posing as a wealthy, advertising executive.