Later this month, "Agents of S.H.I.E.L.D." returns to ABC, plunging viewers back into the shadows, spies and Skye of the Marvel Universe. Given the high-level betrayals at the end of season one, the show's second season is positioned to present the "Agents" in a very different light — or no light at all, as the case may be.

Based on a new synopsis released by ABC, here's everything we know about where things stand when "Agents of S.H.I.E.L.D." returns:

1. Agents of S.H.A.D.O.W.

The remaining S.H.I.E.L.D. agents will trek into darkness when the show returns. Following the Hydra-fueled dissolution of S.H.I.E.L.D., the agency only exists now on the fringe of society, with agents operating in secret, and without government assistance, in their mission to protect those who can't protect themselves from threats beyond their comprehension. It's easier said than done, considering the public now thinks of S.H.I.E.L.D. as foes, not friends.

2. The New Man in Charge

The scraps of S.H.I.E.L.D. now take their orders from Phil Coulson, formerly Agent, now acting as Director, thanks to his appointment by presumed-dead Nick Fury. Generally an optimistic guy, if somewhat monotone in delivery, Coulson's world view was rocked by the Hydra betrayal. He's left with the unenviable task of putting the pieces of S.H.I.E.L.D. back together, without knowing who he can really trust.

3. The Markings on the Wall

Coulson's woes extend beyond his new job. At the end of season one, he was seen etching strange markings into the side of a wall, not unlike duplicitous agent John Garrett's own alien-esque scribblings, fueled by an otherworldly serum called GH-325. Expect those etchings to remain in play when the show returns — and with "Guardians of the Galaxy" now firmly in the zeitgeist, perhaps "Agents of S.H.I.E.L.D." won't shy away from the cosmic side of the Marvel Universe.

4. Come What May

Both Coulson's trust issues and his new habit of writing alien code on walls are firmly on Melinda May's radar. The veteran S.H.I.E.L.D. agent experienced some of her own conflict with Coulson last season, when it was revealed that she was spying on Phil on Nick Fury's behalf. The synopsis for season two tells us that May's cautious eye remains on Coulson "in the wake of the mysterious etchings he's been carving into walls. What do these etchings mean, and can Coulson be trusted?"

5. Clear Skye, Full Hearts, Can't Lose

The new "Agents of S.H.I.E.L.D." trailer revealed a brief look at the new Skye. Chloe Bennett's hacker character has turned a corner, sporting new bangs and banging firepower, now "a full-fledged S.H.I.E.L.D. agent," and aware of her own 0-8-4 status — meaning that she's an object of unknown origin. Under Melinda May's tutelage, it appears that Skye has gone full badass. We like.

6. Grant Your Wildest Wishes

Another character who underwent a severe transformation in season one: Agent Grant Ward, who seemed like a straight-jawed and reliable soldier, but was actually working on Hydra's behalf. All signs pointed toward Ward's demise at the end of season one, but he's still alive and kicking in season two. Well, maybe not kicking, but alive, and behind bars; he's a S.H.I.E.L.D. prisoner now, and the synopsis promises that we haven't seen the last of him.

7. The Fitz Hits The Shan

We haven't seen the last of Agent Leo Fitz, but what we will see moving forward might not be very pretty. He nearly drowned to death in the season one finale, in an attempt to save his best friend (and the object of his affections) Gemma Simmons from suffering a similar fate. Now, Fitz is in a coma, and "may never regain his full cognitive functions; a devastating blow to Simmons."

8. Hunting for New Blood

With Ward off the team and Fitz on the sidelines, S.H.I.E.L.D. needs new recruits. The synopsis clues us in to one of those newbies: Lance Hunter, "a dashing mercenary sharp shooter with a quick wit," played by Nick Blood. But is he a friend, or is he another traitor ala Ward? The synopsis warns that he may have "an ulterior motive for helping out the team," so it's best to remain skeptical.

9. And That's Not All

That's only scratching the surface of what the season two synopsis reveals. We also know that there are a whole lot of guest stars headed to "Agents of S.H.I.E.L.D." in the weeks ahead, including "Xena" herself, Lucy Lawless, as agent Isabelle Hartley, Crusher Creel as the abhorrent Absorbing Man, and "Friday Night Lights" fave Adrianne Palicki as Mockingbird. We'll find out even more once the new season launches in full force later this month.

Agents of S.H.I.E.L.D. returns on September 23.