Big Nick is back on the hunt in Europe and closing in on Donnie, who is embroiled in the treacherous world of diamond thieves and the infamous Panther mafia, as they plot a massive heist of the world's largest diamond exchange.

When the head of a criminal organisation, Finn Wallace is assassinated, the sudden power vacuum his death creates threatens the fragile peace between the intricate web of gangs operating on the streets of the city. Now it’s up to the grieving, volatile and impulsive Sean Wallace to restore control and find those responsible for killing his father.