An absolutely fantastic continuation from Nowhere, Never. The use of Alex and Cass' missing pasts is a fantastic hook for this episode and plays into the ongoing story of how Alex is back and how we end up with Cass in Night of the Doctor. Having the setting be a ship trapped within the void is a particularly great stroke of genius and Hieronyma Friend really proves themselves to be a very interesting morally grey character! I also really like the idea that Cass was a member of this ship before she lost her memories and began travelling with the Doctor. It's a very interesting twist as we thought we knew her story from Meanwhile, Elsewhere, but clearly we didn't. This also gives us a great dynamic with Graff, who, in Cass' previous life, was her lover. A brilliant story and really enjoyed where it ended up!