What we will see in hour 1 is that the CTU detects a possible plot to detonate nuclear devices in five American cities, but they have to stop short and sit on their hands because the Iranian and Chechen terrorists cleverly placed telephone calls to their co-conspirators in the United States.
For the next 22 episodes, we get to watch as CTU tries in vain to get a FISA warrant issued in time to intercept the terrorists' communications. Then, in the 24th episode we get to watch each of the five nuclear devices detonating.
(moved from other thread)
that is a good plot line to be honest. they could cast Lawrence Tribe as the FISA judge, refusing to grant the warrant. then Jack could take him out.