This story was really good! Following on from Cass' ending in the previous story was a great idea. However, this story feels a bit of an odd one as we don't know whether the actual plot is relevant or if it's just a way to have an ongoing story throughout the episode. Definitely a good use of the Time War and the amnesia that seems to come with it. I thought some of the elements were quite funny, such as the singing robot. The ending is left quite ambiguous with it being unclear on how this links up with Cass' return in Borrow or Rob. It's a brilliant story, however, and I think it's a great addition to the boxset, especially as it seems  to be a way of introducing us to what the Doctor and Hieronyma are going to go through in boxset 7.