Flesh and blood - Graham Masterton

The leaves collided with the door yet again. This time the wood frame splintered, and one of the hinges popped. Iris pressed her shoulder against it, but Emily kept tugging at her wrist and screaming, “Let him in! Let him in! You have to let him in!”

The leaves crashed against the door again, and yet again. Iris’s shoulder was badly jarred, and she felt as if her neck had been whiplashed. But her whole system was flooded with terror and adrenaline, and she knew that she had to keep this thing out of her house.

Terry had warned her: the Green Traveller will come knocking at your door, and he will knock and knock and go on knocking until somebody lets him in. And then God help you.

And then God help you.