During a secret mission behind the Iron Curtain, a freak accident involving an exploding rocket shrinks American agent Mel Hunter to the size of six inches. But instead of ending his career, it turns out to be to his, and ₃The Bureau₂s₄, advantage as the pocket-sized operative can infiltrate areas closed off to the average G-man. Hunter is aided by his full-sized partner Agent Bill Winters, gal Friday Miss Brown, and Bureau Commissioner Hall.