4화: 마호, 무니, 린쿠가 선셋 스테이지 대회용 곡 작곡을 위해 피아니스트 레이찬의 도움을 구합니다.
2020년 11월 20일 방영
To gain popularity for their unit and become eligible for the elite Sunset Stage Competition, Maho, Muni, and Rinku decide to enter a contest for a professional unit to choose their melody for their next song. The only problem is, nobody knows how to compose. As a way to speed up their process, they ask the ever so talented Rei-chan, a pianist, to help compose their next song.