Amulet: The stonekeeper BK 1.

Graphic novel star Kazu Kibuishi creates a world of terrible, man-eating demons, a mechanical rabbit, a giant robot---and two ordinary children on a life-or-death mission. After the tragic death of their father, Emily and Navin 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.