As Rin says goodbye to the Remote Magic Tower, he encounters the mysterious (and beautiful) Claire, a member of the Yoizuki Guild. Rin's got an open invitation to join the guild, but before that can happen, he's sucked into yet another dungeon collapse--this time for a B-rank dungeon with tons of high-level monsters pouring out. He agrees to assist Claire in the fallout, but can he keep up with her and survive the fierce battle?