From The Biography Channel:
Well regarded by fans as possibly the best series yet, the Doctor faces deadly foes including the Daleks and his arch-nemesis the Master.
This series also introduces medical student Martha Jones (Freema Agyeman) as the Doctors new companion. Her life as a medical student suddenly becomes much more exciting and adventurous when the Doctor enters her life. Together they travel through time and space, entering amazing new worlds and encountering characters both old and new to fans of the series.
Boasting state of the art visual effects, the third series also features a host of special guest stars including Catherine Tate, John Simm, Mark Gatiss, Michelle Collins, Anthony Flanagan and John Barrowman.http://www.thebiographychannel.co.uk/competition/512/Win_Doctor_Who_Series_3.htm