here's what i think happens, based off of the type of things that happened from previous seasons:
they save edgar somehow, like they did tony when he was shot right in the neck at the mall in a previous season
henderson dies and gives up no information and jack gets arrested for "cruel and unusual punishment" and again becomes a fugitive...and right when los angeles falls into martial law and all the cops are out lookin for jack
so jack, all alone like usual, the rogue cop or "michael chicklis with hair"

, has to solve this thing all by himself (again) while the authorities and the bad guys are out trying to catch him and he he has to catch these nerve gas killers before they strike again
jack bauer does his best work when all parties involved are working against him!!
....
ok, and then here's my fantasy take on finale of the season...remember kim bauer hooked up with a psychologist and she was taken care of by the henderson's? well, they brainwashed her and she too believes somehow the terrorists are the best bet for america, and for cheap, central asian oil for all us suv drivers
jack gets all the terrorists, who never get to attack russia, and when they are down to the last suicidal man, who takes poison to kill himself and reverts to plan "b" as he sends a text message to the leader of plan "b"
the leader of plan "b", while we see the back of his head says he will take over the cannisters...the camera zooms in on the back of his head...and he turns around...it's ramon salazar...:56, :57, :58, :59, :00