There is half a good story here, split into one and a half thirds.

1/3 - Jack Harkness and John Ellis' plot was really good. The scene with John and his aged son was incredible, and the scene with the two of them in the car was very strong.

0.5/3 - Gwen and Emma's story was pretty good, but didn't quite seem to fit together as well as Jack and John. It had its moments, both positive and negative

0/3 - Owen and Diane. I don't care about Owen Harper.