Treating a girl who has ostensibly attempted to jump into the Thames, Dr. Keel discovers that the girl is not the person who was reported to have jumped. Hoping to determine the girl's true identity, Keel and Carol Wilson follow the trail of clues to an East European circus. Figuring largely in the proceedings is one Zibbo the Clown (Kenneth J. Warren), whose jolly face belies his sinister intentions. One of the few Avengers episodes not to feature Patrick Macnee as John Steed, "Girl on the Trapeze" was written by Dennis Spooner and originally aired live on February 11, 1961. ~ Hal Erickson, Rovi