The Isekai Institute took charge of regulating the Sojourners—a group of professional explorers sent on missions to other dimensions. But one day, Solomon Stein—a pioneer—never returned. Countless expeditions searched for him, but all they had brought back was an incomplete copy of his journal. It contained a record of his day-to-day adventures and descriptions of a fabled world called The Paradise. Ten years later, Samwise finally reached the legal age and set it upon himself to find the missing man—his father. But first, he must survive the Institute’s deadly trials and become a Sojourner.