Jack was released by the Chinese so he could be turned over to a terrorist who would then give us the location of this other terrorist who he said was behind a series of suicide bombings in the US. Jack goes willingly like a good soldier until the guy admits to Jack that he is the one actually behind the bombings. Not willing to die for nothing, Jack pretends to be dead and then rips out the throat of his guard with his mouth since he's tied to a chair and can't use his hands. He then escapes. Tells the new president they are going after the wrong guy. The president won't call off the air strike, so Jack rescues the "former" terrorist gone good from the house.
Meanwhile this high school muslim kid is rescued from a mob by a benevelent neighbor and he returns the favor by threatening to kill the guy's whole family because he really is a terrorist (the mob was right!). The kid is too injured to complete his "mission". The father then picks up a component for the kid and delivers it to the terrorists. The terrorist then calls the kid and tells him to kill the hostage. Just as he's about to, Jack rushes in, and saves the hostage.
They end up getting the location of the terrorist headquarters from the hostage who heard the terrorist kid give directions. Jack is forced to shoot that black agent to save the terrorist gone good and so doesn't go on to terrorist HQ. The strike team arrives, begins killing terrorists, but they manage to set off the suitcase nuke right then rather than be captured. The father who delivered the nuke component is still there at the time and gets nuked too.
I've left some stuff out, but that should bring you up to speed.