Ossan Boukensha Kein no Zenkou

Kein, a middle-aged adventurer, who while in the middle of herb gathering, found a rare item Resurrection thought about selling it and turned it into money, but he met a girl seeking medicine to save her companion's looked like Altena, his childhood friend who already died, he gave it in exchange for small , the girl was the strongest adventurer Anastrea, people called her the sword princess. The next day, Kein suddenly got an invitation to join an S rank party, beat down the strongest and the worst monster, miraculously gain lots of money, and finally get confessed by a 20 years old 's simple life will change completely because of his encounter with Anastrea.