Uncle Sam, Buddy and Senator Corey are kidnapped aboard a plane heading for the Panama Canal, and the criminal gang responsible is interested in the papers found in the Senator's briefcase. When they tell the detainees that they plan to use a freighter loaded with explosives to destroy the Gatum Lake Spillway, Uncle Sam disguises himself and frees the other captives and turns the tables on the gang.; The Unkown meets a Nazi commander who took doses of cocaine for additional "courage", but which gave the Colonel super-human strength. Still, he was no match for the innate strength of the Unknown.; An acquaintance of Joch's, the mad scientist Professor Twitch, turns up dead at the hands of Vang, the Professor's assistant. Vang then uses the Professor's formular to create giant killer spiders. Merlin transforms himself into the likeness of Emperor Hirohito to fool Vang and capture him.