There are just four episodes left in season 2 of "Agents of S.H.I.E.L.D.," but there's a lot of action still to come. Marvel and ABC have revealed new images, clips, and synopses for the rest of the season.

First comes a round of stills and the synopsis from the April 28 episode, "The Dirty Half Dozen." There's also a promo that promises an exclusive new look at "Avengers: Age of Ultron." The show's Twitter account has also revealed that Cobie Smulders' Marie Hill will appear.

ENEMIES MUST COME TOGETHER, ON "MARVEL'S AGENTS OF S.H.I.E.L.D."

Edward James Olmos Guest Stars as Robert Gonzales

"The Dirty Half Dozen" - Gonzales and Coulson must find a way to put their differences aside and work together against Hydra, even if it means teaming up with someone they don't trust, on "Marvel's Agents of S.H.I.E.L.D.," TUESDAY, APRIL 28 (9:00-10:00 p.m., ET) on the ABC Television Network.

Tuesday's #AgentsofSHIELD connects w/ @Avengers: Age of Ultron, & has an exclusive from the film! #ItsAllConnected https://t.co/VWYLfctRcM- Agents of SHIELD (@AgentsofSHIELD) April 25, 2015

Episode 20, entitled "Scars," sees Skye trying to balance her connections both to S.H.I.E.L.D and the newly uncovered Inhumans. Airing May 5, the episode also promises a big revelation from Coulson. (via Comicbookmovie.com)

WAR TEARS SKYE APART, ON "MARVEL'S AGENTS OF S.H.I.E.L.D." ON ABC

Edward James Olmos Guest Stars as Robert Gonzales

"Scars" - Skye is torn between her loyalty to S.H.I.E.L.D. and her connection to the Inhumans as tensions rise between the groups -- and Coulson reveals a secret he's been hiding from even those closest to him, on "Marvel's Agents of S.H.I.E.L.D.," TUESDAY, MAY 5 (9:00-10:01 p.m., ET) on the ABC Television Network.

Finally, the synopsis for the two-part season finale, "S.O.S," has also been shared. The two-hour special is set to air May 12. Check out the description below, once again via Comicbookmovie.

"S.O.S.," Part One and Part Two - S.H.I.E.L.D. puts everything on the line to survive a war that blurs the line between friend and foe. Coulson and his team will be forced to make shocking sacrifices that will leave their relationships and their world changed forever, on the two-hour season finale of "Marvel's Agents of S.H.I.E.L.D," Tuesday, May 12(9:00-11:00 PM, ET) on the ABC Television Network.

"Marvel's Agents of S.H.I.E.L.D." stars Clark Gregg as Director Phil Coulson, Ming-Na Wen as Agent Melinda May, Brett Dalton as Grant Ward, Chloe Bennet as Agent Skye, Iain De Caestecker as Agent Leo Fitz, Elizabeth Henstridge as Agent Jemma Simmons, Nick Blood as Lance Hunter and Adrianne Palicki as Bobbi Morse.

Guest starring on "S.O.S.," Part One are Henry Simmons as Alphonso "Mack" Mackenzie, Ruth Negga as Raina, Kyle Maclachlan as Cal, Jamie Harris as Gordon, Christine Adams as Agent Weaver, Mark Allan Stewart as Agent Oliver, Maya Stojan as Kara/Agent 33, Dichen Lachman as Jiaying, Luke Mitchell as Lincoln Campbell, Kyle Mattocks as Agent Harris, Ryan Powers as S.H.I.E.L.D. tech agent and Alicia Vela-Bailey as Alisha.

Guest starring on "S.O.S.," Part Two are Henry Simmons as Alphonso "Mack" Mackenzie, Kyle Maclachlan as Cal, Jamie Harris as Gordon, Christine Adams as Agent Weaver, Mark Allan Stewart as Agent Oliver, Blair Underwood as Andrew Garner, Maya Stojan as Kara/Agent 33, Dichen Lachman as Jiaying, Luke Mitchell as Lincoln Campbell, Brendan Wayne as Jiaying's assistant, Robert Reinis as bartender, Daz Crawford as Kebo, Alicia Vela-Bailey as Alisha and Anthony D. Washington as TAC agent #3.

"S.O.S.," Part One was written by Jeffrey Bell and directed by Vincent Misiano.

"S.O.S.," Part Two was written by Jed Whedon & Maurissa Tancharoen and directed by Billy Gierhart.