Contains spoilers for this episode and earlier episodes.
Tommy's attempt to shoot himself fails because Arthur has removed the bullets. A call then reveals that the IRA stopped the attempt on Mosley and killed Polly as well as Barney and Aberama. The family burns Polly's caravan, and Michael blames Tommy for his mother's death. Their shared grief becomes a promise of revenge rather than a reunion after the failed assassination.
Four years later, Tommy travels to Miquelon as the end of American Prohibition threatens the island's smuggling trade. He has stopped drinking and proposes replacing alcohol shipments with opium. Michael represents interests connected to Gina's uncle, Jack Nelson, but Tommy wants direct access to the more powerful man. He arranges Michael's arrest and uses the possibility of supplying Nelson's rivals to put pressure on the proposed deal.
In Boston, Gina refuses to treat Tommy as an equal to her uncle. Tommy answers by exposing how much he knows about Nelson's movements and by keeping Michael in prison while the negotiations develop. A call from Lizzie changes his immediate plans: Ruby is ill and repeating words that frighten him. Tommy prepares to return to England, leaving the business active. He tells Michael that Nelson and Gina will also be travelling, adding another threat to a relationship already poisoned by Polly's death.