Alma Burton, whose marriage to Mark, the owner of a marketing company in the U.S. state of Vermont, is on the verge of divorce, is supposed to go to a mental institution in New York for treatment.

While in the Spanish city, a tour group of American tourists, which includes the secretary Paulette Stone, the lesbian photographer Lisa Sanders and her African-American model friend Naiba, as well as several wealthy entrepreneurs, are exploring Barcelona's sights by bus.

The victim, a young girl, is brutally killed by a murderer wearing a red raincoat who also gouges out her left eye.

The police are initially in the dark, but soon suspect that the perpetrator is in the group's environment, so that each of the travelers is formally classified as a potential murderer.

Nevertheless, the series of murders does not stop and the number of tourists continues to decline until the serial perpetrator is caught red-handed at the end of the film.

In the last scene of the film, the young inspector congratulates his experienced predecessor, who managed to solve the delicate series of murders within a week.