Vicki first appears in the serial The Rescue, a survivor of a spaceship crash on the planet Dido and menaced by the monstrous Koquillion when she meets the Doctor and his companions Ian and Barbara. Still coping with his recent parting from his granddaughter Susan at the end of The Dalek Invasion of Earth, the Doctor invites the teenage girl to join the TARDIS crew.
Vicki is in many respects an ordinary teenage girl. She is a surrogate granddaughter to the Doctor and takes care of him like her own grandfather. She rarely takes the initiative, relying instead first on Ian and Barbara and then Steven Taylor, whom she treats like an older brother. Like many, however, her travels with the Doctor change and mature her. She is the one who persuades the Doctor to let Ian and Barbara use a Dalek time machine to return to their own time in The Chase.
Vicki eventually falls in love with the warrior Troilus when the TARDIS landed during the siege of Troy. After making sure that Steven and the Doctor will be all right without her, she decides to remain with Troilus, eventually passing into legend as Cressida, the name given to her by King Priam.