Amulet Book #1: The Stonekeeper

Graphic novel star Kazoo Kibosh's creates a world of terrible, man-eating demons, a Mechanical rabbit, a talking Fox, a giant robot-and two ordinary children on a mission. After the tragic death of their father, Emily and Nain move with their mother to the home of her deceased great-grandfather, but the strange house proves to be dangerous. Before long, a sinister creature lures the kids' Mom through a door in the basement. Me and Nain, desperate not to lose her, follow her into an underground world inhabited by demons, robots, and talking animals. Eventually, they enlist the help of a small Mechanical rabbit named Miskito. Together with Miskito, they face the most terrifying monster of all, and Me finally has the chance to save someone she loves.