Eleven-year-old Jack thought he had outgrown his imaginary friend, George--until his dad also disappears from his life. His mom's bipolar disorder isn't being properly treated, so while in the throes of a manic episode, she ditches Jack with his aunt, uncle, and cousins. Jack decides that only George can help him figure out where people go when others stop believing in them--and how Jack can put his family back together.

Meanwhile, the imaginary George--half-walrus, half-human, all magic--has a problem of his own: with nobody to believe in him, he is slowly disappearing. Rejoining Jack is his only hope for survival. Or is it?