Tsutomu Nihei, master of the mysterious architectural monolith, brings his genius to bear on the fantasy genre for the first time. Having established himself with hit series like Blame! and Knights of Sidonia, he has now created a gritty, dark fantasy world and populated it with evil sorcerors and unique undead horrors.

Tower Dungeon is structurally similar to the perenially popular isekai genre - the ingenuous farmboy Yuva must accompany a contingent of knights through the increasingly dangerous floors of massive tower on the way to rescue the princess - but Nihei has turned the genre on its head, bringing his unique sensibility to bear on a crumbling world of malformed creatures, wounded soldiers, and labyrinthine darkness. An evil sorceror slays the king and takes over his body, kidnapping the princess and spiriting her away to the legendary Dragon Tower.

The Royal Guard is rebuffed in their attempt to rescue her, and to replace the wounded, a young farmhand named Yuva is called up into service. With only a potlid for a shield and a strong back to carry supplies, Yuva joins the soldiers on the perilous quest to climb the tower and rescue the princess. But the Dragon Tower houses untold horrors...!