Hiroto Komori lives a calm life with his younger brother Michito, who has autism. One day, a little boy calling himself Lion shows up at their house.
After Hiroto gets a message on Lion's phone directing him to a specific place, he tells Michito to look after Lion and sets out to find the location.
Hiroto believes he may have found out who Lion's father is. Later, he takes Michito and Lion to go see Michitoโs art on display at the zoo.
After Lion suddenly comes down with a fever, a worried Hiroto takes him to the hospital but realizes he doesn't even know how old the boy is.
Kudo writes an article claiming that Aoi is still alive. A mysterious man tells Aoi her cover has been blown and helps her evade the police.
Hiroto reads a news article about Aoi and wonders why she would tell such a blatant lie. Later, he learns the stunning truth about her and Lion.
In hopes of keeping Lionโs whereabouts a secret, Hiroto takes him to an island with Michito. Meanwhile, Shougo visits the Komori brothersโ house.
With Yurugi's help, Aoi heads to Sado to reunite with her family. Later, she explains her actions, and Hiroto expresses his pent-up frustrations.
Hiroto and Michito hurry to the Tachibana house to rescue Aoi and Lion but find no one there. Meanwhile, Aoi and Shougo come to an agreement.
Inspired by Michito's decision to participate in an overnight trial at a new artists' group home, Hiroto takes action to rescue Aoi and Lion.
Michito worries that Hiroto has left home because of him. Meanwhile, Hiroto wanders aimlessly through Tokyo and recalls childhood memories.