A knight dies and is reincarnated into a baby Behemoth, an S-rank monster that looks just like a cat! A novice D-rank adventurer, Aria, adopts him as her kitty cat!

Aria and Tama visit the armor shop of their familiar blacksmith, Vulcan, to have Tama's armor tailored.

Disappearances plague the neighboring town of Lenard and the demon, Beryl, is behind it all. Aria accepts a quest to save the people in trouble.

Tama takes on the earth dragon, his fated enemy, in order to save Aria from the brink of death. Tama turns into a real behemoth!

Stella continues making passes at Tama with her telepathic skills. Meanwhile, Tama feels uneasy as he watches her fight, driven by her old earth dragon instincts.

The group is caught up in a new forest labyrinth. Tama and Aria are excited to explore an untouched earth said to be full of rare materials and rarer treasure chest.

Aria and friends desperately search for Lily and Feri. According to Vulcan, the Earl of Gladstone is rumored to be kidnapping young, beautiful women.

Lily and Feri join Aria's party. Aria is rewarded with a promotion to A-Rank Adventurer! Meanwhile, Tama unlocks the ability to evolve into his third behemoth form.

By invitation of the emperor, Aria and company travel to the imperial city of Klareal. There they meet legendary hero Prince Julius and the Holy Demoness Belzebuth.

With news that one of the Demonic Four has returned to the labyrinth in Ruine, Aria's party, Julius, and Cedric's knights make way for its deepest depths.

After escaping to the demon world, Vasaago's next stop is Aria's birthplace: Lumines. His target? The Philosopher's Stone.

The battle against Vasaago for the fate of the world has begun. Tama evolves into his third behemoth form and takes to the skies with Aria to retaliate!