Princess Magenta, seen skipping in a poster, draws Jonathan into her world, a kingdom threatened by the evil power of the Black Pearl of Osis. Jonathan learns he is destined to liberate the kingdom from that evil power. After being trained by Master Cobalt, a wise old man, Jonathan unlocks the magic power of Princess Magenta's skipping rope and turns it into a beam-throwing weapon. Together with Princess Magenta, the Chihuahua Monte and two magic skipping ropes as their weapons, Jonathan sets out on a dangerous quest to destroy the Black Pearl of Osis and lift the mystery that surrounds its owner. On their way they face death, separation, traps, floggings, dungeons, traitors and a fight in the coliseum. When, finally, they come face to face with the owner of the Black Pearl of Osis, the story takes a surprising twist and the children's loyalty to each other is severely tested.