Book of Earth (Diadem Series)

Score falls victim to a deadly illness with only one cure: stopping the mysterious person behind this magical attack. Determined to save their friend, Helaine and Pixel go to Score's hometown, the Earth city of New York, to seek out his attacker, who is using Score's most precious item to hurt him: his mother's amulet. Finding the amulet proves to be difficult on Earth-an unfamiliar world of cars, skyscrapers, and guns for Helaine and Pixel-where their magical powers are severely weakened. Luckily, the trio stumbles upon a wealthy businessman who promises to help them in return for curing his disabled daughter-but is he really on their side? And then there's Bad Tony, Score's abusive father, fresh from jail, who shows up with gun-toting thugs to kidnap his critically-ill son. Will Helaine and Pixel find the amulet in time to save their dying friend?