Please understand now: If you do not wish to have a major season-three plot point spoiled for you, then close this tab now. The following news will ruin everything. We repeat: Do not read this. But if you are brave and/or prefer to be prepared for the worst, then here goes. Dan Stevens is officially not returning for season four. The Christmas special (which aired in the U.K. last night) explains why, at least as far as Matthew is concerned; for his part, Stevens says he "wanted a chance to do other things." Other things like moving to an undisclosed location in order to escape all the heartbroken and now viciously angry Downton fans, we'd guess.