With the nuke out of the picture, Jack returns to CTU where Tony has been appointed director, which means the man who secretly helped him in Day 1 is likely to become an annoying bureaucrat now. In fact, Tony insists everything be done by the book, especially since a recording found in Syed Ali's apartment indicates he was backed by three Middle Eastern countries and effectively closes the case. Or at least it would, weren't it for Ali's claim that the conversation featured in the recording never took place. Jack and Michelle (Reiko Aylesworth) believe him, but have a hard time convincing Tony and President Palmer. Ali being taken out by a sniper doesn't help that much either.
Whereas other drama shows, like The Sopranos, have calm moments after particularly eventful episodes, 24 can't, by its nature, stop for one second. Major explosion that killed a recurring character? No problem, it can be followed by an assassination that casts doubt on everything that has happened so far. That's the beauty of this series: it never allows you to take it easy.