S.H.I.E.L.D. has located the ancient city depicted in the alien writings Director Phil Coulson and others had been drawing incessantly, but HYDRA holds the key to unlock the temple inside that could set off a mass casualty event.
In a new sneak peek for "Marvel's Agents of S.H.I.E.L.D.", Coulson gathers his team to explain their next mission to locate the temple, buried beneath San Juan, Puerto Rico, and "blow the hell out of it."
The director informs the group that HYDRA has the obelisk and an "expert" who knows how to use it. Bobbi Morse reminds the team that while she and Simmons were undercover, Daniel Whitehall was planning an extinction-level event to kill millions of people. It's safe to assume the power locked inside the obelisk and the event have a correlation.
The teaser for the episode before the winter finale also shows Skye and May rushing to rescue Raina before Whitehall can scoop her up, and one team member may make the ultimate sacrifice to discover the secrets to the alien city.
Chloe Bennet, who plays Skye, recently teased a close connection between her and Raina. The show will further explore what powers the two women may share in the upcoming episode.
"You'll find out that Skye and Raina have something in common - and it's not that they're brunettes," Bennet told TV Guide. "Some of our überfans think the two of them are aliens. Or maybe they're something else - something different and special. It's all leading to a reveal that's mother-effing crazy."
The episode entitled "Ye Who Enter Here" will also revisit the blue alien whose blood brought Agent Coulson back to life. Executive producer Jeffrey Bell has confirmed the alien as part of the humanoid Kree race, the same species as Ronan the Accuser in "Guardians of the Galaxy."
The team may have found the Kree's ancient city, but they still have yet to find out the alien race lives on in another world.
