قسمت 1: ریتو در حال مدیریت زندگی مدرسه‌ای است در حالی که مومو ثبت‌نام می‌کند تا برای او یک هارلم بسازد.

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The story begins with Rito rudely awakened by each Deviluke alien. Rito explains his routine life and is most concerned with Momo due to her deceptive intents. As Rito arrives at school, he meets Haruna. Lala tries to encourage Rito to confess to her, but Rito pushes Lala to a corner and explains to her the situation is complicated as people are legally allowed to marry one person. Out from nowhere, Celine clings onto Rito. Momo and Nana surprise everyone that they have enrolled in their school. Now students, Momo winks at Rito, reminding him of the conversation last night in the bathtub. Momo overheard Rito's concern about marrying multiple girls and explained to Rito that many girls love him and marrying them all would make everyone happy. As the future king of Deviluke, he can have many concubines. Momo vows to create a harem for Rito. During class, Momo becomes popular among the boys while Nana greets a mysterious girl looking out the window. Nana impresses her with her ability to understand animals. The girl introduces herself as Mea. Later, Momo finds Yami at a bench. As Yami is an obstacle to her harem plan, Momo tries to secretly enlist Yami in her harem plan by convincing her to enroll. The conversation gets cut short when Rito runs in panic stating that the other boys suddenly went violent. The other boys arrive on the scene and attack Yami, forcing her to use her weapons. After Yami and Momo restrain the boys, Yami hears a mysterious voice reminding her that she's an assassin assigned to kill Rito. (Source: Wikipedia)