Actors Clark Gregg and his wife Jennifer Gray pose during Amazon's premiere screening of the TV series "Transparent" at the Ace Hotel in downtown Los Angeles, California, September 15, 2014.
Actors Clark Gregg and his wife Jennifer Gray pose during Amazon's premiere screening of the TV series "Transparent" at the Ace Hotel in downtown Los Angeles, California, September 15, 2014. Reuters/Kevork Djansezian

"Marvel's Agents of S.H.I.E.L.D." Season 2 is set to feature an explosive midseason finale. Episode 10, titled "What they Become," will be the final episode before the show takes a long winter break and returns in spring. Fans must brace themselves to witness some jaw-dropping events as the storyline takes some intriguing twists when everyone comes out of the hidden city and are changed forever. Here are a few spoilers on "Marvel's Agents of S.H.I.E.L.D." Season 2 Episode 10 "What They Become." Read on to find out how their misadventure ends. [Warning: Spoilers Alert!]

The last-aired episode opened with a dream sequence and proceeded with its hidden city plotline. The agents of S.H.I.E.L.D. and their boss Coulson successfully discovered the city under San Juan and the way to unlock it. Meanwhile, HYDRA attempted to kidnap Raina, who is very important for S.H.I.E.L.D. Coulson dispatched May, Skye and Hunter to save her. Raina revealed a big secret about the hidden city to Skye. She told her that only the "worthy ones" can safely enter the temple, while others may risk their lives by forcefully trying to infiltrate it. Furthermore, it was revealed that the alien who created the Diviner was Kree.

Raina was attacked for the second time while they were in the Bus. Grant Ward came to take Raina and kidnapped Skye too. He promised Skye that he would make her meet her father.

Coulson and Mack headed to the temple. When Mack entered, he touched some alien patterns, which transformed him into a monster that was determined to destroy everything around him. With his superhuman powers, he attacked his team members as well. Furthermore, Whitehall commanded Agent 33 to destroy the Bus. Toward the end of the episode, Coulson made a tough decision to have the opening of the tower sealed with Mack inside it. Skye and Raina were in Ward's custody and Agent 33 was coming after May and the Bus.

Moving on to Episode 10 of "Marvel's Agents of S.H.I.E.L.D." Season 2, the network has presented a brief synopsis, teasing exciting spoilers on its official website. According to the report, the segment features the ultimate battle between Coulson and Whitehall's teams. This war will reportedly "change everything."

HYDRA and S.H.I.E.L.D. finally come face to face in an "explosive confrontation." As mentioned in the press release, the combat is going to "dramatically alter everyone's fate." Episode 10 "What They Become" is set to feature some highly anticipated moments and unveil the lurking mysteries. The midseason finale revals Skye's shocking past. It seems she is finally going to meet her father, who will bring out the answers to the secrets.

The network has released a promo video (as published on YouTube.com by Television Promos) of the Season 2 midseason finale, giving a glimpse of the action-packed episode. The trailer showcases a few moments from Skye's reunion with her father and it seems she is not too happy to see him. She accuses of him being a murderer and calls him a monster while her other teammates battle it out with HYDRA.

According to Forbes, the midseason finale is "quite possibly the best episode of the series to date." Furthermore, in its spoilers-free review, the website states that "where the episode goes in its final act is to a place few ever expected the series would dare." As per the report, fans must brace themselves to discover the answers "to every immediately important question they've had since the premiere" by the end of the segment.

The upcoming segment was written by Jeffrey Bell and directed by Michael Zinberg. "Marvel's Agents of S.H.I.E.L.D." stars Clark Gregg as Phil Coulson, Brett Dalton as Grant Ward, Chloe Bennett as Skye, Ming-Na Wen as Melinda May, Elizabeth Henstridge as Jemma Simmons and more. Season 2 Episode 10 "What They Become" airs Dec. 9, 2014 at 9 p.m. ET on ABC. Watch the midseason finale promo video below:

Marvel's Agents of SHIELD 2x10 Promo "What They Become" (HD) Winter Finale

Credit: YouTube.com/Television Promos