With the leader back at the lab, Mac comes to a stunning conclusion. He recognizes a foreign accent, and thinks this is an IRA terrorist. An FBI agent, Candace Broadhurst, was once killed when she found a possible link to the group ("Sweet 16"). The leader and Mac get into a showdown, and Mac is left standing after a wall explodes.
Wow! This action-packed episode left viewers on the edge of their seats. Everyone involved rose to the occasion. Danny and Lindsay had sex, big whoop. This was bound to happen. Good thing Danny took her shift, because I doubt she would have handled things the same way. Adam gets a major storyline! About time. I got the impression his being tortured brought back memories of his dad being a bully ("Some Buried Bones"). Danny thought so, too. He used a brotherly pep talk to propel Adam to action, while Mac and Flack did their jobs. Flack remained calm throughout everything, despite the possibility of friends dying in the line of duty.
This is the second straight year of finale explosions ("Charge Of This Post"). However, Mac Taylor can always take care of himself.