allow the ghosts to go through walls) i have a problem with this as it is not explained how they can't get in the room if it is explained in the following part (before the flood) than i have no problem with it. anyway the crew explain that the ghosts only come out at night.so far there is only two ghosts but after a small amount of time another one of the crew members is killed by one of the ghosts. the doctor has to go back in time to when the spaceship landed and he needs to find out why this is happening. the episode ends with the doctor 