After hearing from the slave of the Magic Mirror that she isn't the fairest one of all in the worlds, Queen Grimhilde orders Imhotep and a monster named Crumummy to steal the beauty of all the attractive women of Angel Grove.
Grimhilde disguises herself as an old hag and visits Angel Grove to see if her plan is working. In the process, she tries to poison Mike, but he and the other Rangers figure out who she is. Mike morphs into Magna Defender and returns the beauty to its rightful owners while the Searchers defeat the mummies in combat.
Unfortunately, this doesn't please Bowser one bit as he uses a magic fireball to trap Grimhilde in her old hag disguise as punishment for allowing her vanity to lead her to strike out on her own.
(To be re-edited for future clarification)