Leorus, an adventurer, was abandoned by the guild and received a dismissal notice. His skill “Install” only allowed him to read and memorize information from recorded media like books. Everyone in his party, especially Kainz, looked down on him and scorned him as the holder of a trash skill. Then, on the day of a dungeon expedition, Leorus advanced together with Kainz and the others, but suddenly a powerful enemy appeared, putting the group in grave danger. As Leorus faced a life-threatening situation, he mustered all his strength and reached for a mysterious book before him. A enigmatic beautiful girl appeared…!?