The more I read, the less sense this is making.
Apparently the Gelth attack Earth, then the Cybermen (**** knows which Cybermen) pop up and side with the Gelth (**** knows why). Then the Daleks attack Earth (which Daleks and why they're attacking Earth and the Gelth are complete unknowns). Time and space are fracturing. Jack comes back. Rose 'dies'. Some people are talking about The Master being behind it all, others are saying it's the Time Lords trying to bring themselves back, like the Gelth tried to do. Mickey's somehow mixed up in all of this. There are dead people walking the Earth, possibly as part of the Gelth attack.
This is either going to be the best episode ever, or so ****ing complicated I'll need to rewatch it fifteen times just figure out what the **** is going on.