Liz Shaw is hired by Brigadier Lethbridge-Stewart to be scientific advisor for UNIT. She at first seems sceptical of a need for such an organization dedicated to combating alien invasion, but she soon learns to appreciate it after the events in Spearhead From Space.

Although Doctor Elizabeth Shaw is an accomplished scientist, an expert on meteorites with degrees in several disciplines, including physics and medicine, she soon realizes she knows relatively little as compared to the Doctor, and soon becomes little more than his assistant when he becomes stranded on earth, and is offered a position at UNIT.

Is it any wonder that Liz eventually decides to move on to other opportunities rather than stay just to hand the Doctor his test tubes and tell him how brilliant he is.