The Doctor lands on what appears to be a subway platform. Soon, he finds himself chased by zombie-like creatures. As the creatures appear to gain the upper hand, a masked figure suddenly rushes the zombies. They are quickly dispatched, and the Doctor's shadowy saviour removes her mask. She introduces herself as "Angel", one of the Guardian Angels who patrol the under-city. She explains that the zombies were in fact called "Cannibals", in deference to their eating habits.