Sonna Kazoku nara Sute Chaeba?

For as long as Ichika could remember, her family home has followed some strange “rules.” Her mother, Kazumi, decided that her father, Reitaro, must not cross the tape that had been placed all over the house. Her parents have not conversed for as far back as Ichika could recall, and her father is forbidden from talking to Ichika or Kazumi, instead forced to live in a dark, cramped room while eating and sleeping in isolation. Although Ichika finds her family’s situation strange, she’s unable to talk to her father due to her mother’s strict control.
As her 18th birthday approaches, she decides to solve “the family quiz” and start to converse with Reitaro. Her father than confides in her, revealing the reason for the tape around the home might be because something he had said had hurt Kazumi. Meanwhile, he attempts to communicate with Kazumi in order to change the family’s situation, but when he crosses the tape, Kazumi reacts in an unbelievable way.
After confiding to Kurashiki Sayako about his situation, who had saved him from being hit by a car, she gently advises him that it seemed like “domestic violence.” Ichika tries her best to stop Reitaro from drifting away from Kazumi in a wish to reconcile with her family. But as she delves deeper into the mystery of the tape, she uncovers an unbelievable “lie” that her parents have been hiding all along.
(Source: Drama-Otaku)
~~ Adapted from the manga series "Sonna Kazoku nara Sute Chaeba?" (そんな家族なら捨てちゃえば？) by Murayama Wataru (村山渉).