Posted on these forums years back, made a new account and think I have the structure and general plot outline figured out based on the rumored leaks and trailers. Needless to say I'm very excited for this movie.
Here goes, with evidence cited:
Act I
- Boravia is invading Jarhanpur; Superman arrives and stops the invasion single-handedly
- The Hammer of Boravia (Ultraman in disguise) attacks Metropolis in apparent retaliation and defeats Superman (this speculation is based on Jimmy telling Clark that Superman got his a** kicked in the Hammer of Boravia TV spot)
- Superman flees to the Fortress of Solitude and heals (teaser/preview clip, James Gunn also said this scene is close to the opening of the film)
- Clark goes to The Daily Planet and here we are introduced to Lois and Jimmy (I think this takes place after the fight since in the Hammer of Boravia TV spot Lois is wearing the same outfit as when she "interviews" Superman)
- That night, Clark and Lois celebrate their anniversary, and Lois interviews Clark as Superman, setting up the central question of what it means to be good in a modern world of gray morality
- Meanwhile, Lex Luthor has already set his plot in motion to defeat Superman and grows a kaiju in the lab and releases it; he also captures Joey and forces Metamorpho to work for him
- The kaiju wreaks havoc on Metropolis, distracting Superman and the Justice Gang while Luthor, Ms. Tessmacher, Ultraman, and the Engineer infiltrate the Fortress of Solitude and steal recordings of Jor-El; it will likely be hinted here about who Ultraman is behind the mask when the Fortress appears to recognize him
- Superman and the Gang defeat or subdue the kaiju at great cost to the city, and Superman is heavily criticized by the public, likely for trying to stop the kaiju peacefully instead of killing it
- Superman returns to the Fortress after the kaiju fight and finds it has been raided (I think this takes place after the kaiju fight given his suit has the same battle damage while he is crouched over the robots)
- Superman knows Luthor is behind this but is unable to prove it; he confronts Luthor at LuthorCorp but can't do anything to apprehend him (I think this scene takes place after the kaiju fight given that his suit is still damaged during this office confrontation seen in the BTS videos)
Act II
- Luthor corrupts the hologram of Jor-El and portrays Superman as an alien sent to conquer the planet
- Rick Flag Sr., ARGUS, the Engineer, and Ultraman capture Superman after a protracted battle at the Metropolis Meteors stadium; Mr. Terrific tries to help Superman but is defeated
- Luthor sends Superman to the pocket dimension and interrogates him; Metamorpho is used to keep Superman powerless with kryptonite (as seen in the teaser, trailer, and the final trailer)
- Meanwhile, Jimmy Olsen finds out where Superman is being kept inadvertently through provocative texts seen by Ms. Tessmacher, who has a huge crush on him (rumored leaks)
- Lois presents this information to the Justice Gang, but Guy Gardner refuses to help (based on Lois being angry at him in the Guy Gardner BTS video; she's also wearing the same outfit she later when...)
- Lois and Mr. Terrific attack the portal leading to the pocket dimension, as seen in the teaser and main trailer (I'm not certain whether Guy and Hawkgirl have a change of heart and join the fray, as we do see Guy in a sandy area attacking soldiers and tanks, but that scene also looks a lot like Jarhanpur)
- Meanwhile, Superman convinces Metamorpho to help him escape, so Metamorpho generates sunlight that repowers Superman and allows him to break everyone out of the prison and rescue Joey
- Superman rendeavous with Lois and Mr. Terrific but is heavily drained by the effort, perhaps wounded
- Lois brings Clark back to the Kent farm to recuperate (this is based on the fact that she's still wearing the same T-shirt while she's watching over him and his parents)
- Clark is devastated by the revelations that he might have been sent to conquer the planet; Jonathan Kent tells Clark that his choices make him who he is (Father's Day TV spot)
- On the news, Luthor's portal to the pocket dimension has become unstable (probably due to some side experiments he's been conducting throughout the movie), opening a massive rift in Metropolis (trailer and final trailer); Luthor tries to stop it
- Clark sees this on the news and suits up again with his suit cleaned by Martha Kent (trailer)
Act III
- Superman arrives and tries to stop the destruction with the help of Mr. Terrific and Krypto (final trailer)
- Lois somehow gets involved along with The Daily Planet crew (they are flying Mr. Terrific's craft in the final trailer)
- Luthor is infuriated when Superman earns the support of the people; this leads to him deciding he'd rather let Metropolis die (in the final trailer, he says "They chose him, let them die!") and then orders Ultraman and his henchmen - the Raptors - to let the rift widen
- Superman, Krypto, and Mr. Terrific fight off the Raptors who try to impede their progress
- It is at this point Ultraman is revealed to be a deteriorated clone of Superman when he's unmasked (rumors, final trailer); perhaps Luthor loses control of Ultraman at some point, which could explain why his face is all cut up and his outfit is torn in the teaser
- Superman fights Ultraman/Bizarro and while also closing the portal, sealing his rival on the other side (in the trailer, Superman is flying through debris in a dark environment while dodging heat vision)
- Superman has a final confrontation with Luthor that leaves him shaken and broken
- Mr. Terrific leaves the Gang/corporate sponsorship to form his own team
- At the end of the film, Lois interviews Clark as Superman again, this time at his apartment (ViewerAnon said this scene is not at the end, but I honestly don't know where else it would fit, and also Lois is clearly in Clark's apartment and asks him "you have a dog?" while holding a recorder in her hand; she's wearing the same outfit in this moment as when she's hugging him)
- Clark suits up to join Guy Gardner and repelling the "inter dimensional parasite" (Solaris?) from Metropolis
- At some point, Supergirl arrives at the Fortress and picks up Krypto, setting the stage for her movie
Things I'm not sure of include:
- Hawkgirl tackling Stagg
- When and where Guy is attacking the soldiers on the sand
- What Lois and the DP crew are doing to help in the finale