Nobody talks about the Aqours singles as standalone experiences. Happy Party Train is a 3-minute argument for why that's a mistake. The song itself moves like pure joy translated into sound, built on vocal harmonies that sit in your chest, and the video treats the girls like they exist to deliver that feeling rather than move a narrative forward. It's a palette cleanser disguised as fan service. Watch it when you need to remember what it feels like to be genuinely happy for other people's happiness.

HAPPY PARTY TRAIN is a single-episode music video tied to Love Live! Sunshine!!. It came packaged with the third single from Aqours, the idol group featured in that anime. Fans of Aqours and the wider Love Live! idol franchise will recognize it as a companion piece to that release.