A sweet, kind and funny book by the famous American writer Jennifer L. Holm, a New York Times bestselling author and winner of three Newbery medals. Nothing surprising has ever happened in the life of eleven-year-old Ellie. But one day a fourteen-year-old boy with long hair showed up at her house. He was surprisingly similar to her... grandfather! A great explorer, Ellie's grandfather was always obsessed with the idea of eternal youth. His latest invention is the elixir of immortality. Having tried it on himself, grandfather suddenly began to look younger and turned into a boy. Now he needs to patent his discovery. But not everything is so simple, because the grandfather is a teenager and no one believes in his invention. Ellie and her faithful friends come to the scientist’s aid.