The story takes place in the 93rd year of the Sand Penal Calendar. On a drifting ship named "Mud Whale", there live 513 residents. They are divided into two races - the "Indi" with superpowers, and the "Non-Indi" without superpowers. Compared with the Indi, the Non-Indi have a longer lifespan. One day, a girl named Lycos (voiced by Iwami Manako) was found in the ruins by a boy named Chakro (voiced by Hanae Natsuki). When the boy met the girl, the gears of fate began to turn. Lycos began her life on the Mud Whale. The respected Siwo (voiced by Shimazaki Nobunaga) who is about to become the next leader, Oni (voiced by Umehara Yuichiro) who is full of curiosity about the world outside the island, and the innocent and cute Sammy (voiced by Kanemoto Hisako) who is naive and naive. On the island, every encounter will interweave a new chapter.