A lonely fifth grader tastes absolute power when a mysterious crystal comes into his possession and demonstrates amazing properties. Suddenly, Jonas can make a car float down the street, watch any TV channel in the world, change other people's watches, even make resented classmate Sean Murdock yawn uncontrollably--all by wishing on the blue crystal that a strange, terrified girl thrusts on him. When the crystal informs Jonas that he is an ""Awful Terrible Powerful One,"" his imagination begins to boil with vague plans for revenge and self-aggrandizement. Unfortunately, though, the crystal's crazed former owner, Jacobious Fiar, is hot on his trail; to escape a trap, Jonas lets Sean in on the secret. The girl who gave Jonas the crystal (she's Fiar's daughter Klarinda) reappears as an ally in the struggle to prevent Fiar from availing himself of a rare opportunity to duplicate the crystal's powerful material. In a climactic scuffle, Sean is hurt, Jonas kills Fiar and rescues Klarinda, and the stone is lost. Though Sargent tries to make him a hero, Jonas is too self-centered to be really admirable. The crystal's humorous possibilities are capably, if briefly, exploited, but Fiar doesn't get much chance to be sinister, and the violent conclusion is at odds with the story's generally light tone. Fans of Gormley (Paul's Volcano, etc.) may enjoy this; but thoughtful readers will find more to chew on in Townsend's ambiguous exploration of a similar idea in The Persuading Stick.