Attempting to cover the Chinese takeover of Hong Kong, Sarah Jane Smith stumbles upon alien activity. The Tzun have been trapped on Earth while searching for the location of a lost ship that will allow them to leave. But with the CIA, the Chinese Secret Police, and UNIT on the ship's trail, it won't be easy. Sarah discovers that the Tzun have the wisdom and ingenuity of the Doctor on their side, but finds they are not being put to the best use. Available in October.