After a long time, Wataru has decided to leave his family home and live on his own. The girls have also decided to split up and most of them are living separately as well. But none of them have forgotten about their brother and still stick together to meet him. (Source: AniDB)

In Edo in the mid-1800's, fireworks maker Seikichi Tamaya and his friends struggle to live under the harsh morality laws imposed by the strict city councilor, which ban all luxuries, including fireworks. One day, a strange girl stops by Sekichi's shop with an equally strange request: she wants Sekichi to build a firework that can reach the moon.

Ryuunosuke Natsume is the son of genius inventor Kyusaku Natsume and overbearing Akiko Natsume, CEO of Mishima Heavy Industries. Using funds from his wife's company and the brain from his son's beloved cat, Kyusaku creates a revolutionary android called Atsuko "Nuku Nuku" Natsume. To Kyusaku's disgust, Akiko wants to use her husband's technology to create weaponized robots for her company's customers, resulting in Ryuunosuke getting caught within the explosive fights between his parents The android Nuku Nuku tries to live as a normal high school student, adopting the role of Ryuunosuke's elder sister, but usually ends up acting as her family's protector. Nuku Nuku will do anything to protect the ones she loves.

This is a special to To Heart: Remember My Memories, which includes fighting scenes between all the female characters.