Mad Men Season 7 Spoilers What will happen in the Season 7 Part 1 finale of "Mad Men"? Photo: AMC

Can you believe the Season 7, Part 1, finale of “Mad Men” is already here? It feels like just yesterday we were watching Don Draper drown his sorrows in a bottle of booze while making friends with a cockroach. But according to reports, all of those memories will be left in the dust when episode 7 airs Sunday at 9 p.m.

So, take a break from planning how you’ll be celebrating your Memorial Day weekend and spend a moment to prepare for the most-talked about finale of the spring with five things you should know before “Waterloo” airs:

1. What does “Waterloo” mean?: The definition of waterloo is a decisive or crushing defeat or setback. It comes from the Battle of Waterloo, which was fought on June 18, 1815, near the town of the same name in present-day Belgium.

A French army, under the command of Napoleon, was smashed by the armies of the Seventh Coalition led by the Duke of Wellington. Who will suffer the “Waterloo” of the Season 7 finale?

2. Synopsis, please!: The summary for episode 7 says that “Don will be troubled by a letter; Peggy might seek a new future on a risky venture; Roger will receive a phone call and Pete and Cutler butt heads.”

Pretty vague, huh? The reason for yet another scant summary is that showrunner Matthew Weiner has sworn the cast and crew of “Mad Men” to keep the storyline under wraps.

3. John Hamm hints at emotional ending: You might want to grab some tissues, “Mad Men” fans, or maybe stock your fridge with ice cream, because Hamm hinted an emotional ending for Season 7.

“I'm not going to say I wish it wouldn't end,” the actor told Huffington Post, referring to final season of “Mad Men,” “because everything has to end, but it is what it is. We're going to have an emotional journey once we wrap it up. We'll walk away and lock the door."

4. Every action has a reaction: Newton’s Third Law will come into play during episode 7. According to Weiner, the season finale will be heavily influenced by the shenanigans that went down previously in Season 6.

"There are consequences to what happened last season, that's all I can say," he hinted during a Q&A with AMC. Hmm, could this have something to do with Draper getting fired from SC&P? Don being forced out of the agency was a pretty big moment for “Mad Men.”

How do you think that could possibly affect the Season 7, Part 1, finale? Considering the synopsis suggests that Don will get an alarming letter, we’re almost positive the “consequence” involves him.

5. Theories gone wild: We’ve heard our fair share of “Mad Men” theories, but nothing caused our skin to crawl more than the one of Megan’s death. Fans have been speculating Mrs. Draper’s demise since the moment she put on that white T-shirt with a red star. But is there any truth behind her comparison to Sharon Tate?

For those who don’t know, Tate was an American actress and a sex symbol who shares an eerie resemblance to Megan. You can check out all the creepy similarities here. In 1969, Tate was brutally murdered by members of the Charles Manson’s “family” and because of that, viewers are convinced Megan will follow in her footsteps. Do you? That would be some ending to Part 1 of Season 7.

What do you think will happen in the finale on Sunday night? Chime in below with your predictions. We’d love to hear them!