As an unknown criminal steals the priceless Spoonmaker Diamond from the Topkapi Museum, Merrill (
Gavin MacLeod) informs the crew that they will be sailing on the Stella Solaris cruise ship to their next destinations: Greece and Turkey. Travel agent Dana Pierce (
Polly Bergen) wants to check out the locales for business purposes. Emmett and Ella Stokes (
Harvey Korman and
Nancy Dussault) insist they have seen fellow passenger Mark Hayward (
Mike Connors) before and they tell him so, but he repeatedly denies it. Crusading reporter Joe Novak (
Kiel Martin) is quietly dating Sabrina Drake (
Jan Smithers), whose mother Amanda Drake (
Alexis Smith) he libeled in his columns. When Doc (
Bernie Kopell) finds out that Sabrina is pregnant, he gives serious consideration to marrying Sabrina and being the unborn child's surrogate father. Photographer Cliff Jacobs (
David Hedison) runs into his ex-wife Monica Brandon (
Linda Evans) on board and wants her to model for him, but she won't do it until he has a definite assignment. Years ago, Julie (
Lauren Tewes) sponsored a Greek male child named Gregori Papanopolis (
Lorenzo Lamas) through a world relief organization. Now that she's visiting Greece, she looks him up and finds that he is a wealthy businessman. So they spend time getting reacquainted. Inspector Akmed Sadu (
Jamie Farr) of Interpol boards the ship and demands that Captain Stubing detain several passengers, including Mark Hayward (Connors), whom Sadu seems to know.