Callie, Bailey and Richard present pivotal surgical cases from their pasts when Derek restores the hospital lecture series.
An eighth day of pulse-pounding action begins as a retired Jack Bauer is unwillingly entangled in an assassination plot against visiting president, Omar Hassan.
CTU apprehends a suspect in the thickening assassination plot, but Chloe's convinced they've got the wrong person. Meanwhile, Dana's past returns to haunt her.
