Adventurer Kyle has been steadily working solo for ten years since he was expelled from the party for being incompetent.He is now 30 years old, and people think it is time for him to retire from being an adventurer due to his declining physical strength,

The final battle with the Demon King. Hero Sion had the Demon King cornered, but was betrayed by the four beautiful girls who were his companions, and they were all blown up with the Demon King.However, saved by the Demon King, Sion miraculously survives