Mel wants to go swimming so the Doctor takes her to a tower block called Paradise Towers where there is reputed to be a fantastic pool. When they arrive they discover that the place is far from being the superb leisure resort they had expected - it is run-down and dilapidated.

The hallways are roamed by gangs of young girls known as Kangs; the apartments are inhabited by cannibalistic old ladies, the Rezzies; and the building is managed by a group of dictatorial caretakers, presided over by the Chief Caretaker…