The information arrives that there's a secret Galactor base in the Andes. Ken and Ryu go to the Andes in disguise in order to contact the intelligence member Yupanki. However, Galactor makes them drink some medicine, whereupon they lose their memory, forgetting their task and their names. The wandering Ken meets a dying man who says he has been hired by another man named Yupanki. The man entrusts him with a silver coin, as Yupanki told him to do. Without remembering Yupanki's name, Ken follows the man's last will and gives the coin to the man's daughter Kena. As it is, Ken decides to settle in that Indian village, living together with Kena, and falling in love with her. Meanwhile, Joe and the others discover Ryu who also lost his memory, and find out what antidote would help. Ken is at the same time fortunately stung by an Inca-Scorpion. Its poison is the aforementioned antidote and it negates the effect of the medicin. Ken regains his memory. Then, based on the sketch glued to the silver coin, they detect the enemy base hidden in some ruins and destroy it. But for Ken, it's a sad good-bye from Kena.