Mary and Marshall travel to Providence, RI to observe their witness' trial when Dominic Difazzio becomes a star witness against his uncle and mob boss, Vincent Difazzio. Given Difazzio's murderous track record with explosives, he's not one of Mary's favorites.
After settling into his new life in New Mexico, Difazzio opens a local fish store and falls in love with a business neighbor named Naomi. The only problem is that he doesn't know how to act around women, having never been on a date. He begs Mary for a little advice, and she grudgingly agrees.
Mary says her goodbyes to Raphael, only to run into him later when she accompanies Difazzio on his first date. Difazzio's date goes swimmingly and he tells Mary that he thinks he sees wedding bells in his future. But when Marshall and Mary go to Naomi's home to check on the lovebirds, they're surprised to find another man in the picture. Mary is handed the task of disclosing this information to Difazzio, hoping that his reaction isn't explosive.