Over The Rainbow Session is the Prism Queen Cup in Pretty Rhythm Rainbow Live. It was won by Juné Amou at the age of 13, making her the current Prism Queen, and it's assumed that she will participate in it again. However, she lost to Bell Renjoji in Episode 51. It is held every four years.
Afterwards, everyone found out that Jin's spy messed with the list so that Edel Rose can take the crown, his father, Kō, issued a new list.