For the season 4 finale of "Mad Men," creator Matthew Weiner really pulled out all the stops, making viewers' minds explode with several plot twists while costume director Janie Bryant hit us over the head with amazing frock after frock.

With each female lead making at least three costume changes in episode 13, there was almost too much eye candy to handle for retro-fashion fans.

Joan donned her signature royal blue curve-accentuating dress with a darling silk scarf at the neck (one of our favorites in her wardrobe), as well as a black mock turtleneck number that showed the bodacious redhead to be a bit thicker around the middle than usual.

SPOILER ALERT: The recently promoted office manager reveals late in the episode that she's pregnant. That's right folks, a maternity dress-clad Joan Harris is right around the corner!

Other highlights include Peggy's sharp-collared gray-blue dress (we love the buttonless front and matching skinny belt), and basically Betty's entire season-finale wardrobe, which consisted of classic Audrey Hepburn-esque pieces such as cinched-waist shirtdresses in blue plaid and light gray, plaid pants cropped at the ankle, and a couple of to-die-for swing coats in camel and bright blue.

Also of note was Don's secretary Megan, played by Jessica Paré, who -- DOUBLE SPOILER ALERT! -- is set to become Mrs. Draper, to the dismay of many fans.

While Megan's in-office looks are always especially bright and '60s-rific, we also got to see her in a more relaxed state in California, where she dons a swoon-worthy floral-print bikini, a white tank dress with pink and orange flowers painted along the flared hem, and a simple LBD with a diamond-shaped cutout at the chest as well as a beaded neckline.

Honestly, we can't blame Don for being smitten.

Do you have a favorite look from season 4? Let us know in a comment below.

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In related "Mad Men," news, watch Bryant talk season-4 style.