As Rose Tyler embarks upon her first big TARDIS adventure with the newly-regenerated Doctor, they discover a sinister hospital run by strange cat people and run in to two old acquaintances, The Face of Boe and Cassandra.
Faced with the trauma of a brutal assault, young chemistry prodigy Sarah Mathis, grows desperate to expedite her healing process and agrees to the use of an unusual method of therapy that involves the latest form of artificial intelligence, Raptus.