Katy Manning returned to portray Delyth.
Official summary Edit
A dense fog, as well as a full blown alien war have descended on a small village. Luckily the Doctor and Rose have just arrived on holiday.
As a piece of alien weaponry poses an existential threat to mankind, the Doctor has to team up with a local poet as they try to unravel the mysteries of why a Lady has been seen walking over the surface of Llyn-y-Van Bach Lake, and why all the animals nearby have been dying at midnight. And there is another problem for the Doctor: the Ogrons have returned.
- Writer - Scott Handcock