As the fourth season begins, Janet has given birth to a baby boy---whom she fears prefers Tommy to her. But Tommy has a bigger problem: He's suspected of starting the beach-house fire. Meanwhile, Jerry's son asks him to be his best man at his commitment ceremony; Richie wants Franco to marry Natalie; Lou and Theresa get distracted in church; and the volunteer firefighter (Jennifer Esposito) who rescued Tommy from the beach house takes an interest in him---and isn't shy about letting him know.

Source: TV Guide