In the ruins of Tokyo, Natsu, Arashi and Semimaru meet the sole survivor of Team Winter. Team Spring reaches Mt. Ogino Fuji and finds Natsu's message.
Arashi decides to search underwater for signs of humans but is suddenly confronted by a giant fish. When it tries to attack him, it is suddenly killed by a huge spear thrown by the bearded man accompanied by two wild dogs. His name is Takahiro Aramaki, the only survivor of the Winter Team who died fifteen years ago.
Meanwhile, Hana and the Spring Team find the same flooded cache as Arashi, including food, books, and supplies that are still intact. After they find a letter written by Natsu to any other survivors, Mansaku Tsunomata states that they must accept their current situation and survive. Fearing Takahiro, Arashi, Natsu and Semimaru leave during the night.
Takihiro finds himself alone again with his dogs. He recalls how four of his team were killed by a saber-toothed tiger-like cat soon after emerging. He befriended a wild dog that followed them, but Fubuki was later killed by the same tiger while saving Takahiro and Mitsuru. She later froze to death while dancing in the snow. The dog died from her wounds, but her two pups became the foundation of his pack of dogs. Back in the present, Takahiro sees Hana being chased by a dinosaur-like creature and he uses his dogs to save her.