On the third moon of Delta Magna, The Doctor and Romana I are caught in the middle of an on-going conflict between the local Swampies and the crew of menthane refinery. However, The Doctor will soon have a much bigger problem, to solve. Something huge, and deadly lurks beneath swamps, something which is beginning to wake from a long slumber. Cast Tom Baker (Doctor Who), Mary Tamm (Romana), Neil McCarthy (Thawn), John Abineri (Ranquin) Philip Madoc (Fenner), Glyn Owen (Rohm-Du