Toru Acura and his sister Akari, former saboteurs feeling lost after the end of a major war, as they are hired by the mysterious sorceress Chaika Trabant. Chaika, who carries a large coffin, is on a quest to gather the scattered remains of the late Emperor Arthur Gaz to give him a proper burial. Their journey puts them in conflict with groups like the Gillet Corps, who are tasked with investigating and dealing with the "Chaika situation".

Emperor Gaz's remains, introduces new challenges like the tournament at Hartgen, and reveals mysteries about the Chaikas' origins, including a potential secret island. The season pits Chaika and her companions against the Red Chaika and the hero Lady Claudia. Key plot points include the investigation into the possibility that some of Gaz's research was taken to a mysterious island and the shocking discovery that King Stephan's daughters are also Chaikas.