[DUB] Gate Keepers 21 (2002)

Miu's school friends notice that Miu seems distant depressed. Miu's friends decide to take her to a karaoke lounge to try to cheer her up. They are in a singing room when an interruption occurs in the form of a power outage. Suddenly, Invaders start swarming all over the place. Ayane hears about the Invaders at the karaoke lounge, and goes to help.