Let me tell you this, or actually no, let the song tell everything to you in 4 minutes. For anyone hesitating or protecting themselves from Film Red spoilers, don't worry, this is completely safe, it has nothing to do with Film Red other than the singer Ado voices the main lead in the movie, nothing else, no crossover characters, no plot hints, nothing. The same song also played in the One Piece Film Red filler episodes, it has a very weird nostalgic feel for a childhood you've never had, it feels sad, bitter, and familiar but in a beautiful way. Upon hearing the song in Film Redand again in the One Piece anime, I thought the accompanying visuals were okay, they did the trick, and they reflected well on the theme of the song, but man the visuals that ship with the song is something else let me tell you, stunning, out of the world. It's like a mix of Ghibli films and world-class clay art that felt like reading through a magical children's book.

Long story short, listen to Ado more often. Also, is it a coincidence that the names Oda and Ado are a semordnilap? Fate works in mysterious ways.