Contains spoilers for this episode and earlier episodes.
The Lees raid the Shelby premises, and Tommy faces renewed pressure from Inspector Campbell over the missing guns. Campbell threatens the family with punishments that go well beyond an ordinary investigation. The death of communist Stanley Chapman makes the danger clear, while Freddie remains in hiding and Ada is increasingly isolated from her own relatives. Tommy also questions whether John should marry Lizzie Stark.
Rather than continue the feud with the Lees, Tommy takes John to what he presents as another confrontation. The gathering is actually a wedding. John is to marry Esme Lee, joining the two families and ending their quarrel. He is angry that Tommy has decided his future without consulting him, but accepts the arrangement. The celebration brings Ada back among the Shelbys, even though she still resents Tommy's treatment of Freddie.
Ada goes into labour during the wedding festivities. Polly insists that the child's father should be present, and Tommy promises a truce until sunrise so Freddie can safely come to the birth. Freddie arrives and holds his new son, but the police follow and arrest him. Back at the Garrison, Polly strikes Tommy and accuses him of betraying his promise. The wedding has settled one family conflict, while Freddie's arrest tears open another inside the Shelby household.