Overview
- Episodes 1 and 2 aired on BBC One on Sunday, December 7, with all five episodes now available to stream in the UK on BBC iPlayer.
- The series follows a global crisis sparked by an ancient ocean species, known as the Sea Devils or Homo Aqua, revealing itself to humanity.
- Russell Tovey stars as Barclay alongside Gugu Mbatha-Raw as Salt and Jemma Redgrave returning as UNIT’s Kate Lethbridge-Stewart, with Alexander Devrient, Ruth Madeley and Colin McFarlane also featured.
- The tone is described by creator Russell T Davies as tougher and more morally complex than Doctor Who, reflecting a world responding without the Doctor.
- Episodes 3 and 4 are scheduled for Sunday, December 14, with the finale set for Sunday, December 21, and international streaming planned on Disney+ in 2026.