SPOILER WARNING: This article contains major spoilers for the Agents of S.H.I.E.L.D. Season 6 finale.
In the Season 6 finale, Director Alphonso "Mack" Mackenzie, Melinda May, Daisy Johnson, Elena "Yo-Yo" Rodriguez and Deke Shaw just managed to defeat Izel and Pachakutiq. With May on the brink of death, they hardly had time to figure out their next move before Jemma Simmons arrived, scooped them up and transported them back to 1930s New York City.
When Simmons arrived on the scene, May was suffering from a grievous stab wound, a parting gift from Pachakutiq. However, Simmons didn't seem terribly concerned. "She'll be fine," she informed them stoically, ordering her team to put May into a cryochamber. "We'll repair her tissue in a few hours, when she reaches the correct core temperature, but right now we have to move. Quickly, sir."
A little dazed, Mack gestured to the monoliths behind him. "Isn't it a bad idea to leave those behind?" he asked.
"They'll be gone soon enough," she replied, unconcerned.
"How did you do all this?" Daisy wondered.
"We had help, and we had time," Simmons answered.
"Where's Fitz?" Deke interjected.
"I don't know," she told them. Then, to herself, she whispered, "I can't know."
As they loaded everyone onto Zephyr-One, Simmons supplied some vague answers. "The Chronicoms want to establish Chronica-3 as their new home planet, here on Earth. They believe only S.H.I.E.L.D. can stop them, so they sent hunter to destroy S.H.I.E.L.D. and everyone within it," she explained. "We lost the Lighthouse... The Lighthouse wasn't the only point of interested targeted by the hunters."
"Do you want to share exactly where Fitz sent us?" Mack demanded to know.
"I don't have that information yet. I'll scan the terrain," Simmons replied. "We're above New York City. It's completely fogged over. Good thing, because I forgot to activate cloaking. The controls changed when we upgraded."
"You're right. I can see the Empire State Building," Daisy interjected.
"Yeah, but it's the only building above the clouds," Mack pointed out.
"It may be the tallest building the world," Simmons said wistfully.
Slowly, realization dawned on Mack and Daisy. "Simmons, cloaking isn't the only thing you upgraded, is it?" he asked. "You enhanced the jump drive, too. How?"
"Like I said, we had time," she answered, just as the fog pulled back to reveal the skyline of 1930s New York City. Indeed, the aforementioned Empire State Building was still under construction.
It took some time for the truth to sink in and, even when it did, Daisy felt like she needed some liquid courage to come to temrs with it. "I would say I need a drink, but those are illegal now, aren't they?" she posited.
In an interview with CBR, showrunner Jed Whedon confirmed the team has landed in the 30s. "We know we're going to the 30s, but we're also in a time machine. So we'll see what happens," he teased. Since Daisy implies Prohibition is still in effect, that puts them squarely in the early 30s, at least for the time being. Prohibition, an act that ended the legal sale of alcohol, officially lasted from January 17, 1920 to December 5, 1933.
Judging by a scene from earlier in the episode, this plan was enacted by Enoch, their chronicom ally. He saved Fitz and Simmons when the chronicoms invaded the Lighthouse, their headquarters. ""I have a strategy that can save your lives and the lives of your fellow agents, but unfortunately, time is of the essence. We must act now. This will be the hardest thing you have ever done," he said, but the two were unsurprised. When Simmons asked what they had to do, Enoch replied, "Change the natural course of your lives forever."
Changing the natural course of their lives seems to involve exploring S.H.I.E.L.D.'s history. Per Simmons, the chronicoms are looking to target key moments from S.H.I.E.L.D. history, which is why they built a Coulson LMD: "The chronicom hunters have Fury's black box as well as centuries of anthropological research to pull from. Our team needs an expert in S.H.I.E.L.D. history to have a chance of stopping them, to even know what the hunters might target."
That means the team could run into some familiar faces in Season 7. Asked directly about the chance of fan-favorite characters returning in the show's final season, Whedon replied, "We can't say who, but you will see some."
Of course, it is highly unlikely that Agents of S.H.I.E.L.D. will meet any characters from a Marvel Studios film, as Marvel Television tends to react to -- but not impact -- the movie side of the Marvel Cinematic Universe. However, Marvel TV had another S.H.I.E.L.D.-based series in 2015: Agent Carter.
Notably, the eponymous Agent Carter has made a cameo on Agents of S.H.I.E.L.D. in the past: she appeared in flashbacks in two Season 2 episodes, "Shadows" and "The Things We Bury." As such, there is precedence for a crossover between these two shows, even though the main cast never directly interacted.
In the Season 6 finale, the S.H.I.E.L.D. team is in the 30s, which is a bit to early for Agent Carter, as Agent Carter picked up in 1946. However, as Whedon pointed out, they do have a time machine and, thus, the ability to jump from time period to time period. This opens the door for Agent Carter characters to play an active role in Agents of S.H.I.E.L.D. Season 7, especially considering how critical several of these Agent Carter alums were to the development of the organization.
But what does that have to do with Avengers: Endgame? Well, in the end of the MCU film, Captain America traveled back in time and reunited with Peggy, the love of his life. It was heavily implied the two got married and lived a full life together, resulting in the Old Man Steve that passed his shield to Sam Wilson at the end of the movie. That was an emotionally fulfilling end for Cap's story, but it threw a wrench in the Agent Carter series finale, which implied she had a happy life with Daniel Sousa.
By retooling S.H.I.E.L.D. history, Agents of S.H.I.E.L.D. Season 7 could utilize an Agent Carter character like Peggy or Sousa. Since Agent Carter's series finale offered a different happy ending for Peggy, Agents of S.H.I.E.L.D. could go back and effectively retcon the Agent Carter finale in some capacity to make it match up with Endgame. This would solve the plot hole pointed out by fans of the Marvel TV series.
Though Season 7 wrapped filming days ago, answers to the many questions raised by the Season 6 finale won't be answered until sometime next summer. Further, the showrunners aren't spilling any secrets just yet. However, Agents of S.H.I.E.L.D. Season 7 has the potential to solve an Endgame mystery that left some MCU fans scratching their heads.
Marvel's Agents of S.H.I.E.L.D. will return next summer for its final season on ABC. The series stars Ming-Na Wen, Chloe Bennet, Henry Simmons, Iain De Caestecker, Natalia Cordova-Buckley, Elizabeth Henstridge and Clark Gregg.