Tread Perilously celebration of Doctor Who's second 20 years on the air continues with "73 Yards."

When The Doctor and Ruby Sunday land on the Welsh coastline, he breaks a fairy circle and immediately disappears. Ruby's key will not work in the TARDIS and she is forced to fend for herself in the nearby Welsh town. Making her way home to London, she also discovers a mysterious woman is hovering 73 yards away. Whenever anyone tries to talk to the woman, she inspires fear in them and a contempt for Ruby. With The Doctor still missing, Ruby gets on with her life, but will a chance reference to something he told her reveal her true purpose?

Justin and Erik discuss the personalities of the 14th and 15th Doctors. They also get lost in the Welsh countryside for a time. Erik gets into the trouble of modern Doctor Who discourse. Millie Gibson proves to be a capable lead as she takes point in this episode. Erik outlines the true mystery of faith. The ambiguity of the episode leads to differing opinions. Erik's critical English accents re-appears while Justin considers some of his family's past with the British Empire.