Agents of SHIELD season 2 premiere spoilers Phil Coulson (Clark Gregg) will be making plenty of changes to the agency in "Marvel's Agents Of S.H.I.E.L.D." Season 2 premiere. Photo: Kelsey McNeal/ABC

“Marvel’s Agents Of S.H.I.E.L.D.” Season 2 will have to quench Marvel fans’ thirst for the superhero universe for quite awhile. With “Avengers: Age Of Ultron” not due to release until May 15 next year, the ABC TV show will be the only place where fans can glimpse the Marvel Cinematic Universe (until “Agent Carter” premieres). So, what can we expect in Season 2? Check out what you need to know:

1. Rebuilding S.H.I.E.L.D.

As the new director of S.H.I.E.L.D., Coulson (Clark Gregg) will be building the organization from the ground up. His new position will start a lot of the Season 2 plotlines. They have to prove that they’re a legitimate organization working for the common good, and they have to keep Hydra from infiltrating again -- which means that Coulson will be returning to S.H.I.E.L.D.’s roots.

“This a guy who's obsessed with history, loves the history of S.H.I.E.L.D., and we see it in his office with all his doodads," executive producer Jed Whedon told Seat42F. "It’s a return to the old.”

2. Peggy Carter’s S.H.I.E.L.D. Flashback

Hayley Atwell will guest star as Agent Peggy Carter, who was introduced to Marvel fans in the “Captain America” films. She’ll appear in a flashback to the beginning of S.H.I.E.L.D. Since Carter was one of the founding members, she’ll likely be one of the inspirations for Coulson’s return to S.H.I.E.L.D.’s origins. It’ll also tie in nicely to the “Agent Carter” spinoff that will premiere this winter.

3. Guest Stars Galore

“Marvel’s Agents Of S.H.I.E.L.D.” Season 2 will feature plenty of guest stars as the team rebuilds the organization. New guest stars include Lucy Lawless, Adrianne Palicki, Kyle MacLachlan and Brian Patrick Wade. And there will be lots of familiar faces returning as well. BJ Britt will return as Agent Triplett, Adrian Pasdar will appear as Glenn Talbot and Patton Oswald will play another Koenig brother.

4. Comic Book Characters

Marvel comic fans will be pleased to see some of their favorite characters come to the small screen. Carl “Crusher” Creel (Brian Patrick Wade) will appear in the premiere alongside S.H.I.E.L.D. Agent Isabelle Hartley (Lucy Lawless) in the Season 2 premiere. Adrianne Palicki will play Mockingbird/Bobbi Morse later on in the season.

5. Fitz Is Injured

At the end of last season, Simmons (Elizabeth Henstridge) told the team that Fitz (Iain De Caestecker) was alive, but she didn’t specify how well he was doing. Fitz apparently suffered some brain damage when he and Simmons escaped from the bottom of the ocean. He might not regain full cognitive functions, which could strain his relationship with Simmons. The two work together as a team, and flying solo would be an adjustment. Fitz’s ego might also be damaged if Simmons doesn’t acknowledge his declaration of love.

6. Ward’s Redemption

Last season, Ward helped Hydra take down S.H.I.E.L.D., but that doesn’t mean he’ll be gone forever. The double agent was seen in a holding cell in the “Marvel’s Agents Of S.H.I.E.L.D.” Season 2 promo, so it looks like he is in S.H.I.E.L.D. custody. Actor Brett Dalton has been vocal about making sure fans know that he doesn’t believe Ward is strictly evil. “I like to consider myself an antihero, not a villain,” Dalton told Seat42F.

7. May’s Past

“Marvel’s Agents Of S.H.I.E.L.D.” Season 2 will reveal a little bit more about the mysterious Agent Melinda May (Ming-Na Wen). “She’s gone through something crazy in Bahrain that we’ve hinted at and we will explore in this season,” Whedon told Entertainment Weekly. The Bahrain mission earned May her nickname “The Cavalry.”

8. Skye’s Father

One of last season’s big cliffhangers was Raina (Ruth Negga) giving Skye’s (Chloe Bennet) photo to her father. Although we didn’t see his face, Kyle MacLaughlan will be playing the role, Entertainment Weekly reported. It doesn’t seem like Skye will learn her father’s identity immediately, though. He’ll first appear in Season 2 episode 2 as The Doctor.

9. GH.325

Skye and Coulson still have GH.325 in their systems, and no one knows what side effects are coming. At the end of last season, Coulson was seen writing in what looked like a strange alien language. Judging from the latest billboards for “Marvel’s Agents Of S.H.I.E.L.D.” Season 2 (below), Coulson will definitely still be dealing with that side effect.

“Marvel’s Agents Of S.H.I.E.L.D.” Season 2 premieres Tuesday, Sept. 23, at 9 p.m. ET on ABC. What do you think Coulson is writing? Share your theories in the comments section below!