Unless you happen to be living on Elm Street, having a nap doesn't usually yield dire consequences. Yet poor companion Tegan manages to find the worst planet in the universe to fall asleep on. Because she unwittingly allows herself to become possessed by the ancient evil known as the Mara; a being that dwelt in the Dark Places of the Inside and sought physical existence by taking over a host in their dream. It also allowed Janet Fielding the opportunity to deliver her best performance as evil Tegan. On the planet Deva Loka, Tegan falls asleep among such suspicious-looking wind chimes. The Mara used Tegan to attempt a physical return, threatening the peaceful Kinda tribe and the human colonists that had arrived there. Defeated by the Doctor but not driven from Tegan's mind, the Mara used her to guide the Doctor to its home planet of Manussa from which it had been banished. This time, the entire planet, and potentially the wider universe, was in danger by an enemy seeking revenge. The motto behind this tale; if you encounter wind chimes on an alien planet, don't take a nap. You don't know what will be waiting for you in your dreams.