I've marked it [spoilers] because here's a clip from the episode. Plus the trailer!
[video=youtube;OtIqFgZ0QfQ]https://www.youtube.com/watch?feature=player_embedded&v=OtIqFgZ0QfQ[/video]
[video=youtube;ETCGtZUn_tU]https://www.youtube.com/watch?feature=player_embedded&v=ETCGtZUn_tU[/video]
Cyberman-tastic. Plus it looks like we find out who Missy is; she seems to be (from what I can make out from the above) collecting all the dead from Earth and turning them into a Cyberman army. Or something like that, at least!
[video=youtube;OtIqFgZ0QfQ]https://www.youtube.com/watch?feature=player_embedded&v=OtIqFgZ0QfQ[/video]
[video=youtube;ETCGtZUn_tU]https://www.youtube.com/watch?feature=player_embedded&v=ETCGtZUn_tU[/video]
Cyberman-tastic. Plus it looks like we find out who Missy is; she seems to be (from what I can make out from the above) collecting all the dead from Earth and turning them into a Cyberman army. Or something like that, at least!