This is, without a shadow of a doubt, one of the scariest and most intriguing episodes of Doctor Who. This is a thrilling psychological ride and you will probably find your own beliefs being thrown into question. Riddled with spine-chilling moments, this is an episode no "Who" fan can afford to miss.<br /><br />Starting from when the pit was opened after the events in "The Impossible Planet", the Doctor and Ida are trapped and are running out of air. With no other alternatives, they decide to find what lies at the bottom of the pit, an event which surpasses even The Doctor's expectations. Whilst there, the Doctor is forced to make what he considers to be the ultimate sacrifice...<br /><br />Meanwhile, Rose and the other members of the Planet try to find a way to fend off the Ood, whose minds have been poisoned by the Beast. Also, is Toby Zed truly cured of his possession by the Beast?