The 999 approached the Planet called Crossroads of Destiny, where its blue satellite planet was about to go extinct. The planet was inhabited by a people who returned to a survivalist society when it ran out of natural resources. Tetsuro met Yaku, a weak hunter who was experimenting with new weapons. When his companion Aya decided to leave him for Mu, Yaku went to confront Mu, but was badly beaten. However, he managed to kill a saber-toothed tiger with a crossbow he constructed, saving Aya and Mu. Though Mu laughed for his lack of physical strength, Yaku was satisfied that a new age of knowledge had started with him. (thetvdb.com)