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.

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!