How are Dr. J. Allen Hynek (Aidan Gillen) and Captain Michael Quinn (Michael Malarkey) going to explain this one?
The season one finale of Project Blue Book airs on Tuesday, bringing Hynek and Quinn's investigations into the unknown to a close -- for now. The History series, which has already been renewed for season two, wraps up season one with an epic adventure proving that UFOs are officially here. Only ET has the exclusive first look.
In ET's clip, our favorite duo are confronted with a new case in Washington, D.C., as a series of unidentified flying objects soar towards them at the National Mall. A foreboding shadow engulfs the Washington Monument, capturing the crowd's attention before a group of mysterious, approaching aircrafts sends everyone into a panic.
Check out the scene in the video player above.
Tuesday's season finale is inspired by the real-life Washington D.C. UFO incident of July 1952, and will see Hynek and Quinn confront their biggest challenge yet to uncover the true nature of the treat before it's too late.
During ET's visit to the Project Blue Book set last year, creator David O'Leary said the show aimed to take storylines from real-life headlines during the initiative's 17 years of investigations, from 1952 to 1959.
"All the headlines in the script are just real-life headlines," he said. "We try to keep as much of the details of the UFO event as accurate as we can to what was really reported."
"I think that's part of what we want to do, constantly remind people that while we're dramatizing aspects of the show, obviously, for the human storytelling and things like that, all the cases, all the weirdness and all the spookiness is rooted in real-life historical events and real-life reports and physical, tangible things you can find online and in history," O'Leary continued. "[We're trying to] bolster it and ground it in reality."
As for what fans can expect from the season finale in particular, Malarkey told ET in January that viewers should be prepared to be thrown for a loop. We're hoping that still means, however, that we'll get some answers after Hynek's resignation, Suzie's (Ksenia Solo) taking control of her mission -- and her apparent romance with Mimi (Laura Mennell).
"The great thing about this show, is that the tables -- and [Hynek and Quinn's] wheels -- are constantly turning," Malarkey teased. "It's a historical thriller noir."
The season finale of Project Blue Book airs Tuesday at 10 p.m. ET/PT on History.