Sheila has a miscarriage, but lies about it to keep Tommy near.
She is watching him, and believes he is becoming dangerous as he takes more and more seemingly unnecessary risks on the job.
The season comes to a close with Tommy's mistake at a fire causing Franco to get hurt, and with Tommy's eventual transfer out of the house after the rest of the crew finds out he has been seeing Sheila and gotten her pregnant.
The protagonist and focal point of the series is veteran New York City Firefighter Tommy Gavin (Denis Leary).
The series follows Tommy's troubled family and co-workers as they deal with real life issues, either with post 9/11 trauma or their own domestic problems.
While responding to a fire at an underground sex club, they discover that the "woman" they rescued is really Sully in a black leather skirt and bustier.