Hollow Earth (Unabridged‪)‬

Twins Matt and Emily Calder have imaginations so powerful that they can make art come to life. Their powers are sought by villains intent on accessing the terrors of Hollow Earth - a place where all the devils, demons, and monsters ever imagined lie trapped for all eternity. If Hollow Earth is breached, the world will be plunged into chaos. If Hollow Earth is breached... the twins are as good as dead.