by Hal Erickson
synopsis
Hoping to break up a counterfeiting ring, Steed takes the place of a forger who is about to be released from prison. Steed's partner Dr. Keel remains in the sidelines awaiting further instructions, which may never come if Steed is unable to elude the other counterfeiters, who hover around him constantly. Heron Carvic guest-starred as Five, an associate of Steed's ubiquitous colleague One-Ten. Written by Richard Harris, "Square Root of Evil" was originally broadcast live on January 21, 1961.
