When Uncle Russ Hollister arrives from California and announces that he plans to search for a lost temple deep in the jungles of Yucatán, the Hollister family plunges into a new series of adventures. Uncle Russ, a commercial artist and cartoonist, has been given a map showing the temple's location and intends to use the trip as an opportunity to gather material for his cartoon strip. But others are also attempting to find the temple. On Russ's flight to Shoreham, a snake has been set loose, and in the confusion his briefcase, containing a picture of the temple, is stolen.

The Hollisters decide to join Aunt Marge and their cousins, Teddy and Jean, in Mexico and soon after their arrival they, too, become involved in the deepening mystery. Among them, the Hollisters manage to locate the temple of the laughing idol and in the process to break up a gang of thieves who have been looting Mexican temples and monuments.

An exciting mystery set against an interesting and colorful Mexican background, this is a story that will be welcomed by all the many Hollister fans.