Jack launches his hunt for the terrorists by re-establishing his old undercover identity, but he's not welcomed back until he proves his loyalty with a shocking `gift'.
Jack's undercover work pays off when he joins a deadly mission; Kim attempts to save Megan from her violent father; Kate confirms Reza's terrorist connections.
Jack finds a key to the nuclear threat; CTU sustains a serious setback; President Palmer uncovers deception on his staff; Kim learns the degree to which Gary Matheson has hurt his daughter.
When the spirit of a girl is released after Lois finds a corpse, Clark and Lois must locate her killer, who has been preying on girls in Smallville for the past 10 years.
Some genetically altered humans with extraordinary abilities must search for a place of refuge before those who created them can exploit their powers.