What happens when Harry opens the rift from the Nevernever into Bianca's mansion?

Bob points out the exact spot in the Nevernever that leads to a room in Bianca's mansion. Bob tries to warn Harry of something, but before he can, Harry opens the rift and enters it. On the other side, Harry finds himself in a room full of vampires; Bianca knew about this entrance and suspected Harry's plan, and was guarding it. The vampires fall on Harry, and everything goes black.