The Challengers hunt scam-artist Manfredo in Southeast Asia, where Prof, Red, and Rocky offend the local tribespeople and are sentence to die at dawn. Claiming right to trial by combat, Rocky and Red face two challenges, but are both aided by a mystery person. Meanwhile, Ace and June find evidence that Manfredo was killed. Finally, Prof conquers his challenge, this time with help from Rocky and Red, freeing the trio, who are reunited with Ace and June. They deduce Manfredo was the secret helper, wanting to ensure the Challs reported his death. They find Manfredo, capture him, and head home.; Multi-Man can now change forms at will with the help of a special element. He turns into an energy being, which draws the attention of the Challengers. He changes into a floating moon-man and a sponge-man to evade capture by Ace and Rocky, who are caged by the henchmen. With his new abilities, Multi-Man plans to gain control of Earth. Later, Red and June free their friends, but Multi-Man takes off in his energy form. He blasts Prof out of a helicopter, but the brainy Chall splashes Multi-Man with an antidote, sending the villain crashing into a mountain, and causing him to lose his memory.