<p>Math whiz Alice Jones has already cracked a mystery or two. She's smart and she's fearless, so who else would her classmates turn to? But when a famous local scientist vanishes from a locked room, Alice and her detective skills graduate to the big leagues.</p><br /><p>Dr. Learner had been working on a top-secret invisibility suit that everyone wants. Rumor has it he's disappeared under suspicious circumstances . . . literally. But is wacky science really behind his vanishing? Or is it something more sinister? Alice won't stop until she knows the truth . . .</p><br /><i>The Impossible Clue</i> is a middle-grade story whose appeal is no mystery, with a protagonist whose charm needs no magnifying glass to detect.