Within our solar system, the balance of Nature has been critically disturbed. Warmongering alien forces are exploiting fertile planets to fuel their military resources. As a consequence, Earth is experiencing unprecedented high tides and strange weather anomalies. Crops are failing and the smaller animals are dying. Susan Grey and her friends, the guardians of Earth’s magical Heart Stone, are called upon to intervene. They are contacted by Celestial Witch Zelda; she sends them a hand written letter via Robbie, her adopted son, who has supernatural abilities. Together with the valiant Elvin clans of Earth, they must make perilous journeys into the ravaged planet of Tane in an attempt to restore the balance on Earth and in the solar system.