To LOVE-Ru Darkness OVA

Synopsis

Suddenly: Mikan gets a surprise visit from her classmates, Sachie Kogure and Mami Nogiwa, who are interested in meeting her brother Rito. Mikan is not optimistic about their visit given Rito's frequent accidents with him falling over and groping one of the girls. The situation gets worse when Rito and later the Deviluke sisters greets Mikan's classmates, making Mikan panic. Despite a near accident with Rito slipping on a remote control, the day appears to end well with both of them leaving peacefully until Mikan slips on a shoe and fall on top of Rito right when one of her classmates returns to retrieve her manga. Meanwhile, Momo makes a note of Mikan's classmates.

Mobile Phone: Rito accidentally steps on his cellphone. He fears he will have to buy another phone but Lala offers to fix Rito's phone. Rito accepts. Lala hands Rito an improved model of his phone and has him try it out on Yui who Rito wanted to call to thank for lending a book to Celine. When Rito calls Yui on his new phone, his voice on the receiving end stimulates Yui's senses, bringing her down to her knees. She feels as if Rito's voice is physically molesting her body. As Rito talks about the book, the stimulation on Yui gets worse eventually making her unresponsive. Rito, clueless about the situation, thinks the phone is still broken. Momo offers Rito to try the phone on her and quickly passes out when she hears Rito's voice, revealing the real problem with Rito's improved phone.

Moonlight: On the night of the full moon, Rito panics when he finds a naked girl on the rooftop while watering plants and quickly barges into Mikan. Mikan identifies the girl as Celine in her adult form. Everyone is surprised at Celine's rapid growth given that she did nothing unusual previously. Mikan feels a little sad about losing Celine but Rito assures Mikan that Celine is still present. Wanting to celebrate, Celine asks to sleep with Rito and Mikan for the night. As they all go to bed, Momo, who does not understand Celine's species completely, wonders how the full moon could have affected her growth. The next morning, Celine has reverted to her baby form.

(Source: Wikipedia)