"Come out, come out, wherever you are!" That command is familiar to everyone who has played the children's game, Hide and Seek. The words and game take us back to an innocent carefree time in our lives, where the simple goal was to find hiding playmates. Many children could even enjoy a spirited game with imaginary friends. But then, imaginary friends can sometimes seem so real for young Emily Callaway, her games of Hide and Seek with an imaginary friend named Charlie have become anything but simple and innocent. Instead, she finds herself in the middle of a series of increasingly nightmarish acts that even her father David cannot stop. Who--or what--is Charlie? David wonders. How can an "imaginary" entity have this kind of hold on her? Maybe Charlie is not imaginary at all, but instead a flesh-and-blood, malevolent presence?