The night of a family birthday party. The mother is tired from work and wants to drink a beer as soon as possible. The father is fidgety and keeps an eye on the clock. A little girl is excited about the sumptuous meal and runs around the house. The intercom rings. There, a "new family member" is standing there... (Source: Official site, translated)

Kazuhiko Nukumizu, a self-proclaimed "background character," accidentally witnessed his popular classmate Anna Yanami being rejected by her childhood friend. Since then, Kazuhiko has become involved with several loser heroines, including Anna.

Ryoka is awakened by flurry of text messages from her mother! Panicked and rushed, Mom is clearly concerned for Ryoka's safety, but she is not too keen on letting her daughter know why. Her reasoning being that nothing could really properly describe what is happening! The world might be ending! And there might be a massive new life-form on the roof of their apartment building! (Source: Denpa)

Third season of .