Hikaru Hoshina, a stargazing middle schooler fascinated by constellations and the unexplained, meets Fuwa, a small alien creature able to open wormholes, and becomes Cure Star to protect it from the Notraiders, an organization hunting Fuwa for its power. Searching alongside new allies for the scattered Star Color Pens and the twelve Star Princesses needed to stop the Notraiders, Hikaru's adventure carries her far beyond Earth and into the wider galaxy. The series follows her team as they visit new worlds and add members from beyond their own planet.