The first step to learning Arcana is to summon a spirit from another plane and merge with it. Loren is in the process of summoning his spirit when Derek, a middle-aged man from Earth, is accidentally summoned instead. Loren and Derek find themselves merged into a single body and must navigate this new world together. While Derek learns about the world of Arcana and discovers that his knowledge of math from Earth can be useful, Loren continues his studies and tries to figure out how to work with his new partner. Together, they discover the importance of mana and wards, and the danger of mismanaging them. As they work to master Arcana, they become a powerful team that can cast multiple spells and protect the fortress from any threat.