Murder in the Crooked House

The Crooked House sits on a snowbound cliff overlooking icy seas at the remote northern tip of Japan. A curious place for the millionaire Kozaburo Hamamoto to build a house, but even more curious is the house itself - a disorienting maze of sloping floors and strangely situated staircases, full of bloodcurdling masks and uncanny lifesize dolls. When a man is found dead in one of the mansion's rooms, murdered in seemingly impossible circumstances, the police are called. But they are unable to solve the puzzle, and powerless to protect the party of house guests as more bizarre deaths follow.
Enter Kiyoshi Mitarai, the renowned sleuth, famous for unmasking the culprit behind the notorious Umezawa family massacre. Surely if anyone can crack these cryptic murders he will. But you have all the clues too - can you solve the mystery of the murders in The Crooked House first?