Digital Spy has had a sneak peek at the episode - which, surprise surprise, has its fair share of drama. As always, we don't want to give too much away, but here are ten teasers for your delectation:
© ITV / Carnival
1. Mrs Hughes has got some important test results to get from the doctor! But it turns out Mrs Patmore isn't the only one who knows about her health issues.
2. What is it about Downton Abbey and letters? Last week, a note almost came between Edith and Sir Anthony. This time around, a message will have a big impact in a different way.
3. Why is Cora feeling "let down" by Miss O'Brien? For once, it's not actually O'Brien's fault (not like that soap incident from series one...)
4. It seems weddings bring out the best in Lady Mary - look out for a sweet moment involving her.
5. Bates's cellmate problems are not improving - in fact, they take a turn for the worse. He even uses a naughty word (I know, I know.)
6. With all that money bother, the family takes a trip to one of their other homes for a picnic. But what's Violet's plan for when she leaves Downton?
7. Lady Edith loses her appetite.
8. Someone calls Anna a rude name. Anna!
9. "Everything's alright with me. But it'll be all wrong with you before too long, mark my words."
10. Someone singing a song is a surprisingly sweet moment.
Downton Abbey airs on Sunday at 9pm on ITV1.
Photo gallery - Downton Abbey episode three:
Copyright: ITV Carnival
