Summary: Stuart and his mom, Clarisse, have just moved to Vermont. Stuart does not want to go to a new middle school, Ben and Jerry's. When the class goes on a field trip, Chuck, the class bully humiliates Stuart at the Lighthouse where Stuart is protected from a nasty fall. Later that night, The Shadow reveals himself to Stuart and explains that he is in trouble because he was not supposed to detach from Stuart.

The Shadow is called to The Shadow World while Stuart is sleeping and finds out that unless he can reattach, he will be stretched from dusk to dawn and that Stuart could dissolve. In order to reattach, The Shadow must find light that is strong enough to bind the two. He is given a couple of weeks, until the next full moon, to reattach, or else.

Stuart does not want The Shadow to reattach to him. He gets into trouble at school when he tells off The Shadow, but is overheard by the principal, who thinks Stuart is telling him off. Stuart gets detention for what the principal thinks he said. Shirley, a girl at school who is interested in Stuart, decides to get detention also so that she can see Stuart. The Shadow poses as Stuart and asks Shirley to the school dance.

The Shadow's trial starts a week early because The Shadow has not been trying to reattach himself to Stuart. This is the first time a Shadow has detached from a human, so it is a very important trial in Shadow World. The Shadow is given one more week to reattach.

Stuart is ready to cooperate. In an effort to reattach, The Shadow and Stuart go to a big mirror and lighting store, but while there, the store explodes and Stuart is arrested. Stuart and The Shadow argue, and Stuart finds out that he will be changed into a shadow forever if he falls asleep, so he works hard to stay awake, but he gets arrested again for breaking street lights in order to get rid of The Shadow.

The Shadow decides that they can reattach at the Lighthouse, so they climb to the top. Shirley follows Stuart there, and falls through a step. Stuart chooses to help Shirley rather than to reattach to The Shadow, and The Shadow helps Stuart rescue her.

The Shadow returns to the Shadow World to face his punishment, but he is told that he will not be punished because while he has not reattached to Stuart physically, he has attached to Stuart emotionally.

Stuart is a changed person. While dressing to see Shirley, he sees his image in the mirror lose its balance and come crashing through the mirror, leaving open the possibility of a sequel, should Me and My Shadow succeed as the producers expect that it will.