doubleofive said:

I think have some major plot points for STID figured out. Possible SPOILERS if I'm right:

Movie starts with the crew helping out a planet that isn't technologically developed (see IMAX 9 minute preview). Kirk no longer believes the Prime Directive is the best around (see "Countdown to Darkness" comics), so the ship is hidden underwater (instead of in space for some reason). The planet is being threatened by volcanos, Spock risks his life to turn the volcano off(?).

After the mission, Kirk is called back to Starfleet Command to get in trouble. On the way back, Harrison blows up some stuff in London. Kirk and Spock are at a meeting where Harrison attacks with a shuttle, killing several Admirals, including Pike (trailers don't feature him after dressing down Kirk for the PD thing).

Kirk wants revenge for Pike's death. He claims its for London and what it represents, but its personal. Admiral Marcus (Peter Weller) won't let him go, but he does anyway.

I'm pretty fuzzy on everything else. So maybe I don't know much of anything.

He, thanks to some clue, pursues Harrison to the Klingon homeworld of Qo'noS, violating treaties and traveling covertly. They find Harrison and fight, with Klingon involvement (probably as a third party and not on either side), but Harrison escapes.

Harrison then proceeds to hijack and steal a secret Starfleet prototype heavy-weapon ship. Maybe he did this earlier in the film, I dunno. Either way, knowing he has this involves Admiral Marcus's daughter, Carol, who does weapons research for Starfleet and worked on the project.

Harrison is coming to Earth, probably to destroy everything, and the Enterprise races home to stop him. Big explosions. Harrison's stolen ship crashes into San Fran, the Enterprise may or may not also crash (but probably not thanks to Scotty).

EDIT: Note: I never said why Harrison is pissed at Starfleet. I have no idea.