Sammy Keyes has got two mysteries to solve. Unless she finds scary Mrs Landvogt's dog in a matter of days, she and Grams are going to be out of a home when Mrs Landvogt shops them to the authorities. Sammy needs to be concentrating on getting yappy little Marique back, fast; but she can't stop worrying about the strange elf-girl she found on the night of the Christmas Parade. Why does Elyssa keep disappearing? And why does it have to be Sammy who feels responsible?