The third season builds on the momentum of the previous seasons and concludes several character arcs. The season centers on a biological threat and Jack's efforts to prevent its release in LA and elsewhere. As before, there is a marked transition between the two halves of the season. The direct threat and a far more formidable opponent elevate the back half above the first. The second half also features a successful small-scale narrative focusing on the effects of the attack on the hotel. Previous characters who have exhausted their usefulness have their narrative concluded, drawing the era defined by Jack's wife's death and President Palmer to a close. The season has done the least service to Palmer, whose otherwise sterling character is sullied by his actions and choices. Compared to the previous season, this season is far tighter with fewer nonsensical plots. While action is clearly at the forefront, moments of emotional depth are naturally incorporated that elevate the season. ( )