Mom wakes Calvin up. As he awakens, Calvin notices it's not very bright. He asks the time. A tentacle taps him as a voice under the bed tells him to jump out of bed. Calvin tells the monsters that was a nice try. Beneath the bed, a voice says that it told the other monster Calvin's Mom doesn't smack her lips like that. The other monster says next time he can do it.

Calvin tells Mom the monsters under his bed kept him up all night. She says she checked when she tucked him in, and there weren't any. Calvin knows. She asks how they got there after she left. Calvin asks if she wants him to crawl under and ask them.

In bed, Calvin says Mom wants him to try an experiment. Mom's theory is that if Calvin doesn't think about them will make them go away. Hobbes offers that the idea of being dragged under the bed and devoured by monsters has a way of gripping the mind. Calvin adds that Mom and Dad don't go away when he stops thinking about them.

Calvin tells the monsters he's going to stop thinking about them. He looks over to see eyes and long claws looming over the bed. Calvin turns the light on and yells for Mom. A voice under the bed tells Calvin to admit it, he lied to them.

Calvin tells Hobbes that they monsters will come out when they turn the lights off. He wants to figures out some way to live with them. Hobbes says it's hard to coexist with things that want to kill you. Calvin says they have to do something. Hobbes says they are. They're staying awake all night with the lights on.

Mom asks Calvin why his room stinks. He says it's because of the monsters under the bed. Mom doesn't believe the monsters are causing the smell. She reaches under the bed and comes out with some cans, bones, and a banana peel. Calvin says the monsters don't eat all the garbage they throw down there to quiet them.