Connie and Kit Blair have flown to Mexico City for two weeks vacation. At the hotel Connie receives a telegram from Mr. Renshaw who asks her to meet with
a jeweler in Taxco named Victor King. Peter Dawson, Victor's stepson drives Connie and Kit to Taxco. Connie meets with Victor and is surprised to find Cedric Mole of Lloyds of London a passenger from her flight in his shop.

Connie meets Kit at the home of Hannah Devotion Troy, an American sculptor who they met on the plane. Later, Victor tells Connie that several of his valuable metal silver molds were stolen in a recent robbery and that Cedric is investigating. Kit and Connie visit Peter's mother in Acapulco and learn that Victor has a gambling problem.

They return to Taxco and stay at Hannah's house. One night Connie returns to Hannah's after a date with Peter to find a man with heavily laden burros leaving the house. Connie follows them to a mausoleum. Once inside the mausoleum the man unloads the burros. In the morning Connie asks about her sister. Hannah mistakes Connie for Kit and tells her that Connie went shopping. She suspects that Hannah is lying about Kit's whereabouts, so she goes along with Hannah's mistake.

Connie tells Cedric what happened last night. They go to the cemetery and discover the stolen silver molds hidden in the mausoleum. Later, Connie tells Peter about Kit's disappearance. Peter goes with Connie to give Hannah the third degree about Kit's whereabouts. They reach Hannah's house to find Kit unconscious. Hannah gives a lame excuse for Kit's condition. Connie reveals that Hannah mistook one twin for the other. Later, with the police present Connie reveals the location of the rest of the stolen silver molds and uncovers an insurance scam.