'The city of Silvershine is divided by a tall, concrete wall. On one side, live the wealthy and privileged humans. The occupants of the other side are curious and extraordinary monsters.
'Zach Morgenstern’s parents adopt Morton, a monster-boy, abandoned and discovered near the Wall. As the only monster on the human side, Morton faces challenges with fitting in. Especially when children of North Silvershine start to vanish, and it appears that the monsters are behind it.
'Zach and Monster-boy take matters into their own hands. Crossing the Wall, they discover the cause of the disappearances – an ancient monster, the Grelgoroth. Buried deep underground, it has, with the help of a human scientist, been gathering power by using the energies of the stolen children.
'Zach and Monster-boy must stop the Grelgoroth, rescue the kids, and escape back through the tunnels to safety before the mine collapses around them.
'What neither of them anticipate, however, is the terrible temptation that Monster-boy feels to unite with the monster Grelgoroth against his adoptive human family.' (Publication summary)