"Childhood Friends"

Rinku suggests performing a rap battle with Muni at the Sunset Stage, to Muni's apprehension. When Rinku struggles to create verses, she visits Muni's house to practice and work out on her exercise game as she had "promised", which irks Muni. Rinku abruptly hands the game's controls to Muni ahead of a boss battle to answer a phone call from Towa. Afterwards, an upset Muni asks Rinku to leave. The next day, Rinku's difficulties continue and Muni walks out. Later, Muni confides in Rei that she feels guilty for breaking her own promise with Rinku to write each other letters after the latter moved to Africa. Rei and Maho decide to intervene by organizing a rap battle for the childhood friends to voice their thoughts. Muni begins by expressing her frustration with Rinku prioritizing her popularity over her, to which Rinku answers she had always kept Muni and the group in mind; when Rinku mentions the broken promise, Muni admits she had stopped writing as the letters made them feel more distanced and was too afraid to apologize; as the song transitions into musical verse, the two confess their desires to reconnect and make amends.