The Adventures of Mirio is a story set in a dangerous world where monster cores are the main source of energy for cities. Mirio is an aspiring mage who is overly cautious and always double-checks everything. He embarks on a journey to find a mentor who can teach him magic and eventually meets Tessa, who takes him on as an apprentice. As Mirio continues his studies, he becomes more aware of the looming threat of the monsters and the potential danger they pose to humanity. With his cautious nature and attention to detail, he is determined to use his newfound powers to protect humanity from the monsters and make a difference in the world.