Like every year, it's Rainbow Day on Pinky Island. Yeepe!! But Carla, the organizer, finds the traditional festivities a little...ordinary. She discovers in Zed the "freshness" allowing to renew the event. Zed and Carla collaborate, congratulating each other on their respective good tastes until, CLASH, they disagree on a shade of blue. Their confrontation will make them lose sight of the priority of the event: a party awaited by all Wash-Mash.