When the evil Empress Geela takes over the Planets of the Pentangle, five teenage princesses escape and disguise themselves as musicians to form a band called SpacePOP. Their mission: Spread the message of freedom, friendship and joy through music. Join the princesses on their adventures as they join the resistance to take down the evil Empress Geela, free their parents, and the people of the Pentangle all while spreading the joy of music, beauty, and fashion.

Katsuma, Poppet, Snoodle, and the other Moshi Monsters must stop evil Doctor Strangeglove and his incompetent sidekick Fishlips from pulverising the recently discovered Great Moshling Egg.