Here at Digital Spy we've had a little sneaky peek at the episode. Now obviously we don't want to give too much away, but read on to get some hints about what you can expect from the final extra-long instalment of Downton action this series...
1. Thomas is in a very serious situation indeed... but he'll get some help from a very unlikely ally (who may then come to regret offering their support).
2. Lady Edith discovers something concerning about her editor.
3. What's Matthew talking about when he says: "It's like the Outer Circle from Dante's Inferno"?
4. Ethel doesn't really want to leave Isobel - despite Violet's best efforts. Can anything - or anyone - change her mind?
5. "So now we can start ****** ******."
6. O'Brien is in proper evil mode, but three little words are going to absolutely terrify her.
7. Tom makes a decision about baby Sybil's future.
8. Lady Mary is keeping a secret... from Matthew.
9. Robert is still furious about Tom and Matthew's plans for the estate. In fact, he has other ideas - involving some investor guy called Charles Ponzi. Um...
10. Alfred does something drastic to "stand up against evil" (oo-er), which could get someone else in serious trouble.
Downton Abbey airs on Sunday (November 4) at 9pm on ITV1.
Photo gallery - 'Downton Abbey' - pictures from the series three finale: