Nana and Saiko are two high schoolers who live in a high-tech city called Clairewood which has been under the care of an AI who won't let anyone in or out of the city. A mysterious cat-like robot shows up, and tells them they have the power to liberate their city.

Cadenza was once a world of music, where everyone sang their unique heart song freely. That is, until they were attacked by a strange group called Coalescence. Now its up to a few Cadenzan refugees to find and train Pretty Cure warriors to fight back and regain their Amulets, items that hold all a person's uniqueness within them.