SPOILER WARNING: This article contains major spoilers for tonight's episode of "Agent Carter," "Smoke and Mirrors," which has not yet aired on the west coast at the time of publication.

Tonight's episode of "Agent Carter" revealed some huge elements of Peggy's (Hayley Atwell) past, including her life before the S.S.R., before Steve Rogers, even before Camp Lehigh and Project Rebirth. The episode also revealed the tragic moment that catalyzed her to leave her quiet life behind to become the agent everyone knows and loves.

READ: Hayley Atwell Weighs in on "Agent Carter's" Season 2 Friends & Foes

In the first flashback, Peggy is about six years old, fighting off dragons in her backyard with her mom and her brother. This would come as no surprise to anyone who has seen Peggy fight before. What did come as a surprise was the flashforward from Peggy being six, to Peggy being in her mid-twenties, working as a code breaker at Bletchley Park. (Side note: Bletchley Park was the focus of Benedict Cumberbatch's most recent film, "The Imitation Game." It played a huge part in winning World War II as the center of all German codebreaking operations in England.) It was mentioned in "Agent Carter" season one that Peggy had a history at Bletchley Park, but in the flashback she looked so meek and unassuming. In this flashback she was also engaged -- and not to Steve Rogers! This would have all taken place before the events of "Captain America: The First Avenger."

Throughout these flashbacks it's revealed that while she was invited to become a part of Britain's covert WWII operations, she turned the job down to pursue her life as a future wife and mother. Peggy is even seen in her wedding dress, which I'm sure is skyrocketing through Tumblr this very second. The wedding ends in tragedy as her brother is killed in action. It's this awful moment that Peggy decides to pursue being a spy, which as we know, leads her right to Steve Rogers (Chris Evans), Project Rebirth and now the S.S.R.

It's gut wrenching to know that Peggy has experienced so much loss in her life. She not only lost Steve Rogers to Red Skull, but she lost her brother to the war. Michael Carter was the one who recommended her for the position in the first place, and she agrees to pursue spy work in honor of him. These glimpses into Peggy's past show just how much she risked and lost to become the agent she is today.

Of course, Peggy had to share the flashback spotlight with Agnes Cully, aka Whitney Frost. The episode establishes something of a parallel between them; though Whitney comes from a much more humble background, both women were scolded for their "unfeminine" hobbies by their mothers and told to accept their lot in life as women and wives instead of overcoming society's prejudices to become something more. Both Peggy and Whitney eventually break their respective molds, though their peers continually try to keep them down. However, Whitney was left to fend for herself; unlike Peggy, she didn't have the support of someone like a brother to push her to become a scientist and star.

The episode reveals a few critical moments of Whitney's childhood in Broxton, Oklahoma. In addition to revealing Whitney's early aptitude for science and her unwillingness to follow her mother's rules, the scenes are one mighty Easter egg. If the name of the town sounds familiar, you probably recognize it from J. Michael Straczynski and Olivier Coipel's run on "Thor," where Thor rebuilt Asgard just above Broxton following one of the Ragnarok events. It's unclear if this will stay an Easter egg, build into Dark Matter's mystical nature or perhaps even tease the events of "Thor: Ragnarok."

Check back for CBR's full recap of "Smoke and Mirrors" later tonight.