Having rescued Bill Potts who is now a Cyberman, The Doctor and his companions have visited another level where the reality is a country side community where the community is under seige from Cybermen. Throughout the episode, we see Pearl Mackie as Bill Potts not as a Cybermen because Bill doesn't realise and accept that she is a Cyberman.
The Doctor and his companions with the help of the towns folk set up barricades and weapons ready for the onslaught by the Cybermen. When Missy and The Master are asked to help, they turn away and decide to leave. Missy has second thoughts about whether she should or shouldn't help. The Master shoots MIssy at the back and continues to leave the ship.
Bill Potts is back as Bill Potts and believes she is dead. The Water Creature from the first episode, Heather turns up from a pool and tells Bill she's now a creature like her and that they plan to go travelling. Heather kisses Bill on the lips.