2. Sarah Jane Smith - The Time Warrior
Several scientists have disappeared from a research compound, and the Doctor is one of the experts called in to investigate. One of his colleagues is renowned virologist Lavinia Smith - or rather, her journalist niece Sarah Jane, who is pretending to be her aunt in the hopes of getting a good story for her newspaper. Like any good journalist, Sarah Jane is full of questions and determines that the Doctor is the best one to answer them, stowing away aboard the TARDIS as a way of discovering what really happened to the missing scientists. Sarah Jane is considered one of the best companions in Doctor Who's 50 year history, and this episode certainly got her started on the right foot. She was inquisitive and courageous, trying to make the best of the impossible when she found herself transported back to the Middle Ages. When she finally did admit to herself that the only explanation for her current situation was time travel, she went on to take full control of the situation and played a crucial role in Linx's defeat.