Dæmos Rising 2004 ( 5.7)

Trapped in an isolated cottage, Captain Cavendish thinks he is seeing ghosts. The only person who might understand and help is Kate Lethbridge-Stewart ... but when she arrives, she realises that Cavendish is key in a plot to summon the Daemons back to the Earth. With time running out, Kate discovers that sometimes even the familiar can turn out to be your worst nightmare.