Due to Hayate's most recent borderline test scores, Nagi gives him some time off to study. Meanwhile, Klaus sends a robotic butler built by Shiori, which looks somewhat like Hayate to fill in for him while he is studying. The robot, known as Thirteen, does an even better job as a butler than Hayate even could, which depresses him when he finds out. Hayate then tries not to get too worried when Sakuya tells him that Nagi and Thirteen get along well. As Nagi realized how jealous Hayate is, she is somehow enjoying his jealousy over her. Thirteen scanned Nagi's emotion, he asked her why is she happy, and as she explained to him about ‘jealousy’, even he doesn't know the meaning. Thirteen devises a plan to get Hayate and Nagi alone together, though only Hayate realizes this after the fact. Nagi grabbed his hand and said to Hayate that he is her only butler, no matter how incapable he is to her. That night, the news reporter informed that a giant asteroid is closing in on Earth, Thirteen goes into space to destroy the meteor, thus saving the Earth and Nagi's happiness, but is stranded on the moon.