This episode was a very strong one. The two minor issues with this episode were that the story with Brendan was very confusing and the cyber drones being cyberman heads was a bit stupid. But apart from those two minor queries this episode accomplished a lot. Bradley Walsh as Graham in this story was really good, especially when he realised that they left Ryan behind. Mandip Gill as Yaz was also really good in this episode. Sadly, Tosin Cole couldn't get up to those standards. The doctor was really well played by Jodie Whittaker in this episode, especially in the beginning and at the very end. The lone cyberman was again very done in this episode and I loved the new cybermen design. But I didn't really care for any of the side characters. The Gallifrey twist at the end was exciting and the master's return was short but very threatening. I adored the concept of the cyber war and how the remaining humans used a rift to travel to a different universe. Overall, this was a very good setup for the finale. 9/10