Sally Sparrow receives a cryptic message from the Doctor about a mysterious new enemy species that is after the TARDIS. Sally Sparrow receives a cryptic message from the Doctor about a mysterious new enemy species that is after the TARDIS. Sally Sparrow receives a cryptic message from the Doctor about a mysterious new enemy species that is after the TARDIS. Sally Sparrow receives a cryptic message from the Doctor about a mysterious new enemy species that is after the TARDIS.