sentences:  Many of the visits are accompanied by a characteristic energy signature which the Doctor does not recognise and sets off to investigate.He travels to 1984 Baltimore, but hears a police report with a search out for the Doctor and realises a future incarnation is already there, so instead decides to visit Australia in 2006.There he is to meet Tegan, an old companion, still trying to reconcile her everyday life with the adventures she had with the Doctor, and Katherine Chambers, a woman dealing with a legacy of events in the Doctor's future.