A Place Called Skull — John Newton Chance

A man comes to find his way into a secret house, but when he finds it he has a feeling that he is already lost. His mission is to save the world from final devastation, but the nearer he comes to that last secret, the greater his feeling of being lost. He meets people in this house, people he seems to know but cannot place. All that he can be sure of is that they are there to stop him going through the last door.