Rui Kamishiro is an ordinary high school student with incredible skills in invention and mechanics. At school, he tries not to attract attention, but for a long time he has been attracted to a guy from a parallel class, Tsukasa Tenma. And for a long time he began to follow him and take pictures on the sly. One day he dreams of locking him in his house and proving that he loves him. That he is his bright star in a dark world and only he makes him rejoice at the new day.