While working together to infiltrate a South Boston Irish gang, an undercover officer and a police informant try to establish their identities. They navigate through dangerous situations and build trust with the gang members, all while trying to gather enough evidence to take down the organization. As the stakes get higher and the risks become greater, the two must rely on each other to stay alive and complete their mission. In the end, they succeed in bringing the gang to justice, but not without facing personal sacrifices and emotional turmoil.