Although they are still mourning the death of their son, Tommy and Janet are moving forward with their separation. Tommy is also still trying to maintain his sobriety while now bogged down with new responsibilities, which include caring for his father. Sean Garrity has struck up a secret relationship with Tommy's sister Maggie, and unfortunately for him, he's really starting to fall for her. Sheila finds condoms in her son Damian's room, and asks Tommy to have a conversation with him about it. In confronting Damian, Tommy learns that the teenager is carrying on an affair with one of his teachers, Mrs. Turbody. And when the city's no-smoking ban threatens the firehouse, the crew tries to make things interesting by starting a big wager on whether they can quit smoking.