Warning: There are many spoilers ahead!

We’ve been studiously trying to ignore everything the UK press has been writing about Downton Abbey season three. (The lucky Brits, of course, got to see it months before we here in the US did.) It mostly worked, so we went into last night’s premiere with that exciting sense of anticipation that only a soap opera-cum-costume drama with posh accents can bring.

The year is 1920, which means fashion is going flapper. All the younger ladies are proudly showing off their slim, bare arms, and beads and feathers are favorites of the Downton ladies of all ages. And how crazy is it that several plot points revolved around menswear? The mysterious missing shirts! Branson’s refusal to wear tails! Wearing the wrong suit to a fancy dinner! It goes on… (And if you doubted Downton‘s fashion cred, did you notice that Ralph Lauren, whose Fall 2012 collection was inspired by Downton Abbey, is now a sponsor of Materpiece? Yup, full circle.)

From Lady Grantham’s crazy American mom (played by Shirley MacLaine) to Lady Mary’s wedding gown (!) (and eww, Matthew’s scandalous dirty double entendres), click through to see how the fashion contributed to the plot.