Three espionage agents--Dutch Holland, Spaniard, and Gertmann--blow up an optical company and make off with a tray of laser rubies, though Gertmann is killed in the getaway. National Intelligence Agency investigator Dan Street learns that Gertmann had been employed by an electronics firm that has just perfected a laser-ray gun capable of disintegrating any target from great distances. While Street continues his investigations (to the disappointment of his wife, Charlie) fashion designer Count Mario Romano, accompanied by Dutch and Spaniard, meets with King Chou Lai to sell him the stolen rubies necessary for operation of the ray gun. Street finds Gertmann's widow, Stassa, who is now having an affair with Dutch, and learns that they both work for Romano. Finally realizing that the enemy's objective is to delay completion of the gun, Street doublechecks with the Defense Department and discovers that Romano's yacht is anchored near the fortress-like electronics building where the gun is kept. Street enters an underground tunnel extending from the building to the sea and eventually encounters Romano and his team of "destructors," who have already worked their way through the waterpipes into the electronics building. Dutch, who was brainwashed by Communists in the Korean War and dishonorably discharged as a turncoat, has a change of heart and helps Street prevent the theft of the gun. Though Dutch sacrifices his own life, Romano and Stassa also are killed.
