Bess Marvin, one of Nancy Drew's best friends, has won a trip to the Bahamas and invites Nancy and girlfriend George Fayne to go along. What starts as a great time in the Caribbean turns into disaster when Bess is kidnapped and held for ransom. Nancy and George end up in a whirlwind quest to find hidden treasure to rescue Bess.

Like previous games, Ransom of the Seven Ships is a point-and-click adventure game. It contains all of the normal elements of a standard adventure - talking to other characters, gathering objects and clues, and solving puzzles. In addition, there are some activities specific to a tropical island - beach-combing, swimming, snorkeling, sailing and scuba diving.

Up until now, Bess and George have only been voices on the telephone. This is the first game in which players will meet both of them. While playing the game, players will alternate characters between playing Nancy and playing George. There are two difficulty levels from which to choose: Junior or Senior Detective.