Nightmares by Jason Segel and Kirsten Miller

Charlie hasn't gotten a good night's sleep in weeks. He's afraid of his dreams, and he believes his new stepmother is a witch. Charlie learns that his nightmares are in the Netherworld, but someone wants to lure him in and trap his body there. When Charlie refuses to let a witch take him there, his little brother is captured instead. Charlie follows them into the Netherworld where he must face his worst fears. He encounters the nightmares of other children, and the son of Medusa helps him. Charlie learns that his own fears are spreading throughout his town, and a creature from the Netherworld has been traveling through a portal between the worlds. The portal will remain open, and evil creatures will invade the real world, unless Charlie can overcome his own nightmares.

There's the lesson; face your fears, or they'll only get worse. The plot includes many common phobias including spiders, clowns, goblins... and gym teachers! The Netherworld is an interesting balance between the complicated thoughts of our brains and how a "real" boy might exist with those thoughts. In addition to Charlie's issues, there's another conflict going on within the Netherworld itself. The president there has changed the way nightmare creatures think, but some of them don't agree with his plans. Two people are stronger than one, and three people are stronger than two. The book is a creepy blend of bad dreams, but it has adventure, emotions, and good beats evil. I was hooked.