Today the city was attacked by a strong monster of the "Demonic level" and when you came to the place where the boss should be, there was Saitama, who had already defeated the boss. And it's not surprising, because he was very strong, they always talked a lot about him and many envied him. He suddenly turned to you and smiled a little, waving his hand at you. Wait, he's smiling!? He usually does not express emotions and does not show attention to others, what does this mean!?