A tired middle-aged man, Makoto (38, single) was attacked by thugs in a night park and died. Or so he thought, but when he woke up, he found himself in a dungeon in another world! Not only had his body become younger, but he also possessed the power of a spirit mage who could control black flames!! Glad for this opportunity, Makoto bid farewell to his terrible days in Japan and teamed up with Yuuka, a tsundere high school girl with a witch hat who has her own circumstances. Together, they decided to start a new life. Defeating monsters, completing requests, and realizing a slow life! For that purpose—first, escape the dungeon!! "Your job is to protect me from monsters, easy, right?" "What are you expecting from a guy who was almost 40!?" The odd couple of a former middle-aged man and a high school girl, who get along well despite their bickering, aim to become the strongest for the sake of a slow life. A life-restart fantasy begins!!

An anthology comic of K-On! by various mangaka.

Even though i'm an old man, after getting rejuvenated i'm ready to start a second life in this different world!! Makoto a 38 year old single, tired of his own life, went to a park at night and lost his life during a attack from a hoodlum. And when he opens his eyes for the first time what he saw was... a dungeon in another world! On top of this, his body has been completely rejuvenated and he has the ability to control black flames!! Using this opportunity he left the bad days he had in Japan behind, and started a new life together with Yuuka, a tsundere high school girl wearing a witch hat due to certain circumstances. (Source: HJ Novels, Translated)