Tiger is a very lucky kid: she has a monster living under her bed. Every night, Tiger and Monster play games until it's time for lights out. Of course, Monster would never try to scare Tiger; that's not what best friends do. But Monster needs to scare someone; it's a monster, after all. So while Tiger sleeps, Monster scares all of her nightmares away. Thanks to her friend, Tiger has nothing but good dreams. But waiting in the darkness is a nightmare so big and mean that Monster can't fight it alone. Only teamwork and a lot of bravery can chase this nightmare away.