Natsuki Takeuchi's brother-in-law is Masashi, who is wandering around Tokyo looking for housing and a job, so he is temporarily staying at his brother's house for a while. One day, to help his sister-in-law avoid burning her hands when she accidentally dropped a frying pan of oil, he ended up severely burning his two hands.
His sister-in-law felt really guilty towards Masashi, so she took care of him very attentively, cooking for him and feeding him in his room, but that still wasn't enough for her husband; Masashi used the excuse that with his hands like that, how could he possibly do certain things? Since he was addicted to those activities, he asked his sister-in-law for help, after all, it was just that, so there was nothing wrong with it concerning his brother.
However, his big… member soon captivated his sister-in-law…