Perpugilliam (Peri) Brown

Peri Brown was a young American student who was on holiday in Lanzarote wwhen she foun herself in the Tardis when she was recued from drowning by Turlough. Despite his warning of the Doctor's nack for getting into trouble, she and and the Doctor confronted the Master and Peri decided to spend her remaining three months' holiday with the Doctor in the Tardis. She also witnessed the Doctor's regeneration into his sixth body, and she stayed with the Doctor until the Time Lords took him out of time. She then decided to live as a warrior queen with King Yrcanos.

Peri Brown was in The Planet of Fire to Trail of a Time Lord: Episode 8 (Mindwarp).