An Anglo assassin has been snuffing out various foreigners in Japan. It's learned that all the victims were secretly part of the Washington Terrestial Defense Force Scientific Team. After an observation rocket studying the "dark planet" of Pedan was mistaken for a pending invasion, the aliens intend to counterattack with their robot King Joe.
“ペダン星人、キングジョー登場”
ワシントン基地が打ち上げた観測ロケットを侵略と判断したペダン星人は、地球に潜入。地球防衛軍科学班の要人を次々と殺害！ さらに、大勢の科学者を乗せて日本へ向かっていた原子力潜水艦アーサー号も沈没させられてしまう!!
