As a lover of psychology, high school student Ritsu Shikishima enjoys contemplating questions like "What is happiness?" while spending peaceful days with his pals. However, everything changes when he hears a garbled voice belonging to famous pop idol, μ, begging for aid amidst static. Her singing has begun to have a negative effect on the world, and Ritsu's loved ones become distorted Digiheads, fierce beasts with a mission to wipe out anyone who is coming to terms with their existence. Ritsu discovers that they're trapped in Mobius, a virtual world created by μ. He must unite with others who have realized the truth and use their Catharsis Effects to escape The Ostinato Musicians while fighting with their emotions-granted powers and weapons.