S1·E19 To the Rainbow Planet: Blue Cat's Secret!

The girls arrive on Planet Rainbow and find its feline denizens petrified before finding Blue Cat's treasure stash where a Star Color Pen awaits. But are soon followed by Eyeone, who reveals herself to have turned the planet's citizens to stone while experimenting with the Aries Dark Pen. Eyeone manages to capture Fuwa in the battle that followed, Fuwa smelling a familiar scent from Eyeone's butler Bakenyan. It is then that Bakenyan reveals himself to be Blue Cat in disguise, the thief revealing herself to be a resident of Rainbow who infiltrated the Notraiders to steal the Star Color Pens from them. A furious Eyeone uses a Dark Pen to turn one of the petrified citizens into a Notrigger, leading Lala to deduce that they still possess hearts and can be restored as Blue Cat uses a flash grenade to keep Eyeone from stealing the Gemini Star Color Pen. The Cures defeat the Notrigger and revive the Gemini Star Princess sisters, offering to help Blue Cat.