As the family prepares for their second child, Hikari gets excited for his new role as big brother, but Masaki is overcome with worry over his new child's future. Later, the family plays hide and seek at Hiromu's family home.

Hikari tries to be a good big brother to Hinata, but works a little too hard. Hiromu's parents try to make up for the years they've lost with their son and his family.

Masaki gathers his courage and brings his family and friends with him to his hometown, but things get awkward when he's confronted by his cousin Kazuhiko.

Masaki settles things with Kazuhiko, then takes his family to visit his parents' grave. Later, Hikari ventures forth on a new adventure: a solo errand.

Hikari wants to befriend the new neighbor's dog, but first he has to stop being scared of him. The family visits Masaki's uncle again, and Kazuhiko awkwardly tries to make conversation with Hiromu.

Masaki and Hikari encounter another new neighbor at the park: single father Mochizuki, who is trying to hold things together for his son Michiru after the loss of his spouse. Masaki offers to help.

Mayhem ensues when Matsuo's younger twin brothers Yuto and Shuto drop by for a visit. First they zero in on befriending Hikari, then they set their sights on Yuki and his relationship to their older brother.

Yuki tries to sort out his feelings toward Matsuo. Mochizuki finally gets the chance to meet Hiromu, but the meeting doesn't exactly go as nicely as Masaki was hoping it would.

After talking it out with Hiromu, Masaki attempts to reach out to Mochizuki and reach an understanding between them.