From Google Translate:

Twenty years have passed since the Demon King was defeated. Raina, who had once been summoned as a Hero but lacked the talent for the sword—leaving him able only to watch his companions set off on their journey—now works alone in the royal capital as an archer, ceaselessly picking off monsters. Then, a young girl named Ariana appears before him as the new Hero, bringing news that the Demon King is poised to return. Burdened by regrets from his past, this middle-aged archer rises up once more—this time as a true Hero and a guardian of humanity!!