Hajime and Hiroshi have been close friends. Hiroshi's mother, Ruri, sees Hajime as a cute boy, and Hajime often comes to Hiroshi's house to study and stay over. However, he often finds himself thinking about Ruri's body. Although he knows that this is wrong, he cannot help but be captivated by Ruri's revealing lingerie. Despite her keen eyes, Ruri notices but cannot figure it out. What Ruri doesn't expect is that Hajime has a 'secret weapon' that is so powerful. And when Ruri is fast asleep on the sofa, an 18cm rocket is ready to be launched toward Mars with Mr. Musk. Will this rocket launch be successful? Will Hajime land safely? How will Ruri face this situation?