A couple thousand years of solitude have done little to mature Asley, an eternally youthful sorcerer who is as foolish as he is powerful. After a lifetime of ridicule for his lack of talent, he retreated from the world to live as a reclusive researcher. During a magical experiment, he accidentally created the Eternity Elixir, granting himself and his loyal familiar, a Siberian Husky named Pochi, immortal life. Thousands of years later, after two centuries of complete isolation, his level 100 canine companion finally demands he go outside and get some fresh air.

The world Asley re-enters is one where the magical arts he spent millennia mastering have long been forgotten, making his abilities seem extraordinary by modern standards. Accompanied by the talking and often bossy Pochi, who is not afraid to offer him blunt friendly advice, Asley sets out on a journey with several goals. He aims to drop the unglamorous titles from his past, restore his good name, and test his magic mettle against a new era. Their adventures lead them to participate in a mysterious competition known as the Familiar Feud, while also uncovering signs of a growing darkness. The revival of a great evil and a Demon King threatens this new world, and the faith of the people has waned, leaving them bereft of the holy heroes needed to combat the threat. As Asley travels, he encounters new companions, confronts the curse of his long life, and slowly begins to mature, if he can endure Pochis constant guidance along the way.