Nolan Burke has gotten rid of one enemy - and bought himself an even more deadly one. After months of coordination with the Syndicate, Seamus O'Brien is finally dead. Nolan and the Syndicate leaders have spent the last five weeks preparing for Baren Maguire's next move, but when it comes, it's even more shocking than anyone expected. Bridget Monaghan isn't free yet. Her debt to Seamus may be forgiven, but killing Baren's son, Sean, means she has an even bigger one to pay. Refusing to hole up on Gerald Island with her parents, she hunkers down in Southie with Nolan, waiting for the right time to tell him about the one remaining secret between them. As Baren makes every deadly move in the IRA playbook, South Boston becomes a battlefield. A new arrival only increases the stakes - and the body count - forcing Nolan and the Syndicate to pull out all the stops in an effort to take control of the territory once and for all. As the situation becomes more dangerous, Bridget and Nolan become locked in a battle for their community, their future - and their very lives.