[Ken Holt 10] • The Mystery of the Green Flame

While en route to Mexico City to meet Richard Holt, his son Ken and best friend Sandy Allen, pass through Laredo, Texas. There they cross the border into Mexico, where the boys witness the green flame for the first time. It becomes obvious that the lighter used to create this effect was meant for another group in a red convertible. After being warned to stay on the highway, Sandy and Ken proceed south to Mexico City, for the Pan-American Conference. When Mort Phillips is picked up as a hitch-hiker and acts suspiciously, the boys realize that they are in the midst of another mystery.

When Ramon Gonzalez of the Mexican Federal Police enters the picture and Mort is identified as an FBI agent, the nature of the mystery emerges. Criminals arrive in Mexico and disappear, with new identities. Ken and Sandy naturally volunteer to assist the two law enforcement officers. It is a criminal called The Baron that the foursome are initially stalking and losing, in the interior of Mexico. However, they do capture a prisoner named Mendoza, who is canny enough to fend off their questions.

Later, as Sandy and Ken continue south on their own, they stumble across a possible criminal hide-out at a hospital in Rio Clara. There they are befriended by a youth named Roberto and are then captured by the gang members Al, Joe, and George. They are taken to Dr. Gosset in the hospital at the edge of town. He is the ring leader of the gang and the one responsible for criminals leading new lives, after plastic surgery with new identities.

When the three boys barricade themselves underground it is only with Ken's intense drive and Sandy's physical strength that the plot of the good Doctor is thwarted. But it is Sandy who devises a means of reaching Mort Phillips via a home made radio. It remains for the trapped youths to hold off the frenzied attacks of the gang, until help arrives. They barely do so and thereby solve The Mystery of the Green Flame.