Sugar grew up in the Toronto Towers during the First Human Empire when most of Earth was uninhabitable. She took a job as a Comfort Mediator for Novalunar Corporation and achieved the rank of Senior Mediator.
Sugar met the Doctor during the maiden voyage of Novalunar's Interstitial Transposition Vehicle where she was working in Executive Class. Using her knowledge of ship technology, Sugar helped the Doctor thwart an incursion of predatory pan-dimensional aliens from a parallel quantum reality. (AUDIO: The Last Voyage)