The Timekeeper (en Inglés) - Bob Jordan

When a glowing pink meteor crashes near Nana's farm, twins Jerry and Keri discover a magical stone pulsing with rosy light. This ancient rock, called the Timekeeper, can heal memories and turn back time. Nana has been forgetting their names and the happy summers they once shared. With the Timekeeper, the twins believe they can bring their beloved grandmother back. But every wish steals a star from the sky, and time itself begins to freeze. Jerry and Keri must make a heartbreaking choice: keep the magic that saves Nana's memories, or give it back to save the world. A heartfelt tale of courage, mystery, and the most powerful magic of all-love that never forgets.