Kerwin Mathews, who dueled a sword-wielding skeleton in The 7th Voyage of Sinbad, now leads the Battle Beneath the Earth. A madman intends to launch nuclear attacks on the U.S. from a network of secret underground tunnels - a scheme Mathews must stop before it's too late and before you finish your popcorn. Events turn real-world and apocalyptic when Yul Brynner is The Ultimate Warrior. After a blight destroys food supplies, New York City teems with ravenous gang. The Baron (Max von Sydow), who has developed vegetable seeds immune to the plague, asks Brynner to take the hope for the future - the Baron's pregnant daughter and some seeds - out of the urban wasteland. Through the subway tunnels they go. Hell follows after them.