The Gathering (Shadow House, Book 1)

Some houses are more than just haunted . . . they're hungry.
Dash, Dylan, Poppy, Marcus, and Azumi don't know this at first. They
each think they've been summoned to Shadow House for innocent
reasons. But there's nothing innocent about Shadow House.
Something within its walls is wickedly wrong. Nothing--and nobody--can
be trusted. Hallways move. Doors vanish. Ghosts appear. Children
disappear.
And the way out?
That's disappeared, too. . . .
Enter Shadow House . . . if you dare.