nine
o'clock
They all three looked at the clock . On school mornings the clock dominated their every instant . Marise often thought that the swinging of its great pendulum was as threatening as the Pendulum that swung in the Pit . Back and forth , back and forth , bringing nearer and nearer the knife-edge of its dire threat that nine o'clock would come and the children not be in school . Somehow they must all manage to break the bonds that held them there and escape from the death-trap before the fatal swinging menace reached them . The stroke of nine , booming out in that house , would be like the Crack o ' Doom to the children . Marise told Paul not to eat so fast , and said to Elly , who was finishing her lessons and her breakfast together , `` I let you do this , this one time , Elly , but I do n't want you to let it happen again .