Diabolical mastermind Harry Crowel, a.k.a. Prisoner 39013, escapes and, with a seemingly endless supply of henchmen, sets out to destroy all holdings of industrialist Horace Granville, who put him in prison. One target is an amusement park, home of the three , who perform death-defying stunts. Aghast at innocent lives lost, our three heroes swear to capture No. 39013. It’ll be harder than they suspect; the villain is holding the real Granville captive, and with a near-perfect disguise, has taken his place!