![Engaged to the Unidentified](https://image.chilimovie.com/public/300px/20190808/uAIQS35hGd4uGP6pKaPiWvMwi5m.jpg)
As Kobeni decides to keep Konoha's true identity a secret from Benio, Niko continues to investigate her, despite warnings from Hakuya. Later, Mashiro and Konoha find some time alone to confirm they are from the same species, with Konoha assuming they were trying to get close to Benio. After Mashiro and Hakuya confirm this isn't the case, Konoha tells Hakuya that, as a male of the same species, he should marry her, which Kobeni overhears.
As Mashiro tries to come to grips with Benio's popularity at school, Kobeni continues to try and remember about Hakuya. Later, Mashiro gets spooked at the thought of aliens existing. Meanwhile at school, Mashiro accidentally lets slip to the class that Hakuya is living with Kobeni.
Just an ordinary teenager, Kobeni Yonomori receives quite the surprise on her 16th birthday—a fiancé and a sister-in-law she never even knew she had. As a result of an arrangement that her late grandfather made, Hakuya Mitsumine and his younger sister Mashiro have moved from their countryside home to the Yonomori household in order to deepen their relationship with their new family members. This story follows Kobeni's "love life" with Hakuya as she tries her best to adjust to the abrupt changes forced upon her. However, as some extraordinary secrets regarding the siblings come to light, Kobeni will find her life changed forever.