A year after Sheila is killed by a hit-and-run driver, her wealthy husband invites a group of friends to spend a week on his yacht playing a scavenger hunt mystery game. The game turns out to be all too real and all too deadly.

Sheila Green (Yvonne Romain) is killed in a hit-and-run car accident while walking home from a party one night. A year later, her multi-millionaire husband, Clinton (James Coburn), invites a group of friends (James Mason, Raquel Welch, Dyan Cannon, Richard Benjamin, Joan Hackett, and Ian McShane) to spend a week with him on his yacht. Clinton loves to play elaborate games and he assigns everyone a secret - one is an alcoholic, another an informer and so on - that they are not to share with anyone. Every day for the next six days, they will call into a port where they will be given clues to discover one person's secret. The game takes a deadly twist when a murder takes place and it all has to do with the game they have been playing and the secrets that Clinton assigned at the outset.—garykmcd

Megalomaniacal movie Producer Clinton (James Coburn) invites six acquaintances on a week-long cruise on his yacht, the Sheila, named after his late wife, Sheila Green (Yvonne Romain). All are B-actors and actresses. On board, they play a game, which Clinton's calling "The Sheila Green Memorial Gossip Game". The game quickly changes when some of the guests figure out Clinton's real motivations.—Huggo