While attending the annual Dungeon Core gathering, perpetually-last-place Rokuko is shocked to learn she's shot up the DP rankings thanks to Keima's help. Her newfound status immediately attracts some unwanted attention from her fellow cores, and soon, she's locked in a dangerous three-way dungeon battle! But what looks like an easy win on the surface proves much trickier than either Rokuko or Keima expect as they go head-to-head with the battle-crazy core, Aidi! Will Keima's cunning be enough to secure the victory?!