The girl's search for the Sagittarius Color Pen leads them to an auction on Planet Zenny, which they manage to attend thanks to an invitation by space idol Mao. When the pen is put up as an auction item, Madoka uses donuts brought in by Pruns as currency to win the audition. However, the pen gets stolen by Mao, whose true identity is revealed to be that of the space phantom thief Blue Cat...