第 1 集: 六組成員儘管缺少回郵地址，仍出席罕見的U4 Fes音樂節

1

The six units are introduced at the Unknown Underground Unbelievable Ultimate Fes. (U4 Fes.), a mysterious music festival that takes place once every 100 years. Happy Around! receives its invitation in the mail, and although the four agree to participate, Rei notices the lack of a return address. (Source: Wikipedia)