Engaged to the Unidentified

Engaged to the Unidentified (未確認で進行形, Mikakunin de Shinkōkei, lit. "Unconfirmed & In-Progress") is a Japanese four-panel comic strip manga by Cherry-Arai. The strip has been running in Ichijinsha's Manga 4-Koma Palette magazine since April 2009. An anime television series adaptation by Dogakobo aired in Japan between January and March 2014. The first chapter was released on April 22, 2009, in the Manga 4-Koma Palette (at the time Manga 4-Koma Kings Palette) magazine's June 2009 issue. The series has been collected in seven tankōbon volumes since July 22, 2010, the latest of which was published on March 20, 2015. The fourth volume was released simultaneously with a limited edition on December 28, 2013. Bundled with it was a DVD with an animated music clip of the song Zentaiteki ni Sensation (ぜんたい的にセンセーション?) performed by Haruka Terui, Eriko Matsui and Yuri Yoshida. An original video animation was released with the limited edition of the fifth volume.

Plot
Kobeni Yonomori is an ordinary girl just starting high school. Nothing unusual happens to her until her 16th birthday when she learns that she is betrothed to Hakuya Mitsumine, a boy the same age as her. Hakuya moves in from the countryside with his little sister and Kobeni's sister-in-law Mashiro Mitsumine and the two start living with her. Not to mention, Kobeni has a sister named Benio Yonomori who is two years older already living with her.

The story revolves around these four people as they try to figure out their roles in each other's lives!