In the world of "Ura Sekai Yako," Sorauo and Toriko embark on a thrilling exploration of another world, deepening their feelings for each other on a winter night. As the seasons shift towards winter, Sorauo and Toriko investigate their base, the "Mountain Ranch," after an attack by a group that worships the lunar month of Uruma. The hidden world is still filled with dangerous mysteries, but that's what makes the allure of unknown exploration so captivating. Sorauo prepares for their adventure together, but a terrifying threat from the past quietly approaches. Toriko seems to have something important to tell Sorauo—there's no turning back from here, as the two girls dive into a survival adventure against the supernatural!