The case -- in which a series of UFOs were seen by a large crowd of people at Washington's National Mall -- raised the stakes for Project Blue Book, forcing Hynek to meet with the president and testify to government officials that the mysterious aircrafts had nothing to do with alien life (even though he was fully convinced otherwise).
"I think it's great that we see Hynek is presented with proper empirical evidence that he's somewhat delighted by," Gillen told ET of the show's season finale. "In the scene at the Mall, the lights are coming over the monument and everyone's terrified. You see a bit there of joy in Hynek, and that's kind of important, too."
Just as important was Hynek taking the lead on making Project Blue Book a more covert operation, convincing Quinn that telling the government there wasn't any truth to UFO sightings was the only way to continue their investigations. "I think [the Quinn-Hynek relationship was] a risk because people may not get it, but I would like to think we pulled that off," he said of his and Malarkey's portrayal of the not-so-odd couple relationship. "Where that's going to go in the future, I don't know, but things have quite established their personalities... I think it's quite a likeable, believable relationship and we'll see where it goes."
"We really see Hynek declare what his future role is going to be or how he's going to play the game," the actor added.
Showrunner Sean Jablonski agreed. "[In the finale, Hynek is] doing something that if you thought about it for a minute, you wouldn't do. You're lying to government officials. You're saying essentially, 'We're going to go undercover now, in our own organization, to find out the truth,'" he said, excited over the results. "That's a great character arc."
Jablonski is also proud of how the show's other characters, including Ksenia Solo's Suzie, have developed throughout the season. As he revealed, Solo's character was meant to have a much shorter arc, but he was so impressed by her acting that the team decided to expand her role. Over the last 10 episodes, fans have seen Suzie add a layer of cold war era to Project Blue Book, help Mimi (Laura Mennell) come into her own as a woman, and now set her sights on Quinn.
"Moving forward, we see Suzie and Quinn at the end of episode 10, you can feel the chemistry there," Jablonski noted. "So, there's a lot of different combinations we can use, and it gets very complicated after what Suzie and Mimi had, and now what Quinn and Suzie could have, and then you bring in the Russian aspect of it too. I think it all dovetails very nicely."
And of course, there's the wrench in Hynek's plans to continue his investigations into the unknown. The season concluded with the astrophysicist being warned not to continue his research -- by the very man who had been encouraging him.
"We've already established the adversaries within the government, and the idea that 'Unseen' had been his advocate along the way, having him turn against him puts yet another obstacle in his path that he's going to have to overcome," Jablonski explained. "'You believe it that much and want the truth, how bad do you want it? Because we're going to put obstacles in your path.'"
"If he's going to go down that path, I guess we need to see there are dangers," Gillen said. "You want your characters to be in peril, but not drastically."
Jablonski looks forward to Hynek "having to put his money where his mouth is" in season two. The series was renewed last month.
"We could not be happier," he exclaimed. "They did say it's the first time they've picked up a show at History while it was still airing. I think that just is testament not just to the ratings, but to the commitment they have over there, and the true passion they have for the show."
Project Blue Book's team of writers have already started meetings on where to take season two. While Jablonski wouldn't give up exactly how we'll find our characters next season, he did say that the team is hoping to "pick up where we left off at the end of season one." That means more of that alien obelisk in Antarctica, which was depicted right before the credits rolled.
"The obelisk we see at the end is obviously modeled after the Washington Monument," Jablonski said, noting that the inspiration stemmed from The United States Navy Antarctic Developments Program's Operation Highjump. "Season two, you want to go bigger. You want to go deeper, and we want to make sure we're topping ourselves. Thankfully, I think we platformed a lot of good story that gives us even more to get into."
"I guess we have to [go bigger]," Gillen conceded. "It's such a big ending to end on. We've got to take it further."