The lack of advance detail about this episode had led to wild speculation about it possibly featuring returning actors, characters and monsters, while Doctor Who magazine even had a redacted cast list last month. Some pondered whether Ncuti Gatwa might put in an early cameo as the Fifteenth Doctor opposite David Tennant. In the end, it was a multi-Doctor adventure of sorts, just perhaps not in the way some people had been hoping.
Effectively a two-hander for Tennant and Catherine Tate’s Donna, it explored a theme we’ve seen before in Who during stories such as Listen or Flatline – that there is something nameless and shapeless lurking at the edge of our understanding of the universe, and it is coming to get us. This time, though, it came disturbingly in the misshapen form of Tennant and Tate themselves.