Contains spoilers for this episode and earlier episodes.
Tommy marries Grace at his country estate, bringing the Shelbys together with guests who look uneasily at their criminal connections. The family has money, a large house and a young son to celebrate, but Tommy cannot leave business outside the wedding. He has been drawn into a secret operation supplying stolen weapons to Russian royalists, an obligation attached to the power that saved his life.
A Russian visitor arrives using a code name that does not match the instructions Tommy has received. Tatiana Petrovna brings money and confirms that a wrong code identifies an infiltrator. Tommy must deal with the man while keeping the danger away from Grace and the guests. Arthur takes him outside and shoots him, making the wedding another occasion on which the brothers conceal a killing behind the celebrations.
Arthur also struggles through his best man's speech and tries to follow Linda's religious influence, although violence remains part of his work for Tommy. Grace wants the family's new life and charitable plans to offer a future beyond the gang. Tommy promises that the next day will belong to them, but later returns to the business with Polly. The celebration ends with him prepared to gamble the family's wealth on a robbery while admitting that he is frightened.