Cardboard is about a boy named Cam who lives with his father; his mother is dead. Cam's father is struggling to find work, and the novel opens as he tries to find something to buy for Cam's birthday. He winds up getting him a cardboard box, being convinced by the toy-peddler that it is a gift that will inspire the imagination and lead to father-son bonding. It's pretty predictable when the toy seller gives the two rules of the cardboard (you can't have more and you have to return the scraps) that something is up with this particular box of cardboard. Sure enough, it turns out to be magic, and Cam and his father ultimately find themselves working against an evil neighborhood boy, Marcus, to keep their find from turning evil.
I did really like the premise of the graphic novel, but I felt like there were too many facets to the story that were underdeveloped. For instance, Cam and his father both mourn the mother, but it's kind of brushed on and left. Also, Marcus - the evil neighbor - mentions that he has bipolar disorder, but then that's dropped.
I do think that this book will be popular in my classroom, I guess I'm just not a huge graphic novel fan.
Also Try: Ghostopolis and Bad Island, by Doug TenNapel; Anya's Ghost by Vera Brosgol