Subaru Natsuki leads a party across a deadly desert toward the Pleiades Watchtower, hunting a way to restore what the Authority of Gluttony took at Priestella: Rem's consciousness, Crusch's memories, and Julius's name. Emilia, Beatrice, Ram, and a handful of allies make the crossing with him, and the tower's guardian Shaula meets them with trials of her own. Season 4 adapts Arc 6 of the light novel.