As Thomas plans to oust Billy Kimber, hidden secrets are revealed and the family have to face up to the problems that have divided them. Meanwhile, Campbell, obsessed with taking down the Peaky Blinders, unleashed one last plan to destroy them.
Inspector Campbell visits Mr. Zhang’s brothel looking for a release after Grace rejects his marriage proposal in the previous episode, while at the brothel, he is greeted by a prostitute who reveals that he is a "special, special customer".
Grace Burgess visits the museum looking for Campbell, only to find Sergeant Moss waiting for her instead. Moss hands her a paper with a letter from Campbell and calls her a whore. The letter states that Campbell knows Grace slept with Thomas.
Campbell hurts the prostitute that he's with while they're in bed together, however she tells him that it's okay because he's a "special, special customer," but refuses to sit with him and talk afterwards. She is crying to Mr. Zhang when Thomas arrives to get his suits.
When Thomas discovers that Campbell is at the brothel, he goes to speak with him, telling him that he thought that he came to clean up the city, not sleep with its whores. Campbell says that he's meeting with Winston Churchill that day to be congratulated on getting the guns back, and laughs because Thomas still doesn't know how he got them. Campbell tells him that his heart will be broken by the time the day is over.
Polly Shelby tells Ada Shelby about her children, and how the police took them away from her. She tells Ada to forgive Thomas because he is the one who brought strength and power to the Shelby family, and will make sure the same thing won’t happen to Ada. She tells Ada that Freddie will be getting out of jail.
Winston Churchill praises Inspector Campbell for his good work, and Campbell tells him that Grace Burgess was instrumental to the success of the case. He tells Churchill that he has a plan for the Peaky Blinders so that they don’t go free, but he doesn't want to have them arrested because he doesn't want them to have a trial.
Thomas leads the Peaky Blinders meeting to inform them of the plan for Black Star Day, in which the Shelbys and the Lees going against Kimber’s men at the Worcester Races. Polly brings Ada and her son Karl to the meeting. She tells Thomas that he is forgiven if Freddie Thorne really is being freed from jail.
The Peaky Blinders free Freddie, with Danny Whizz-Bang manning a machine gun, and Freddie expresses his surprise at seeing Danny, who he thought was dead.
At the Garrison Pub, Grace and Thomas serve drinks to the Peaky Blinders gang. He tells her that he will make sure Grace will be at the next family meeting. Grace tells Thomas that when he comes back from the races, she won’t be here. She tries to tell him of her betrayal to him, but gets interrupted when Thomas finds out that Billy Kimber's men are on their way.
Thomas tells Ada to get to safety because Kimber’s men knew about the Black Star Day plan. Polly tells him that the Peaky Blinders can handle them but Thomas explains that the Lee Family are already on their way to the racetrack, and that without the Lees the Peaky Blinders gang will be outnumbered against Kimber’s men. Polly and Thomas realize that Grace betrayed them.
Polly visits Grace at the Garrison Pub just before she is about to leave. Grace pulls a gun on her and tells her that as an agent of the crown, she has the right to use force if Polly won't get out of her way. They share drinks and Polly tells Grace that though Thomas might accept Grace into the family, Polly herself never will. She tells Grace that if she sets eyes on her again she’ll kill her.
Thomas rallies his men and gives them instructions, saying that the Kimbers will be there in ten minutes.
Inspector Campbell ensures that certain areas will be free of policemen so the two gangs aren't interrupted and can kill each other off. Sergeant Moss is upset with him because he had been excited that Campbell wanted to clear out corruption, but he's just as corrupt.
The Peaky Blinders and Billy Kimber's gang face off on Garrison Lane, but before they can begin fighting Ada Shelby arrives with her infant son Karl and stands directly between the opposing gangs. She tries to convince them not to fight, urging all the men to think of their own wives and children that they'd be leaving behind if they were to die over this feud. Billy Kimber appears to back down, but suddenly draws his gun and shoots Thomas. Danny leaps forward to defend him, and Kimber shoots him too, killing him. Thomas shoots Kimber in the head and declares that the fight is over, ordering Kimber's men to leave. They take Billy Kimber's body and go.
Grace goes to Campbell's office to ask him what he said to Tommy. He says that he told him that by the end of the day, he'd have his heart broken. Campbell tells her that it appears that she's broken two hearts. She says that she's broken her own as well.
Jeremiah Jesus takes the bullet out of Thomas's shoulder while Arthur Shelby cleans him up. Over Danny Whizz-Bang's body, the Peaky Blinders bid him farewell and share a drink, then go to celebrate the win against Kimber.
Moss tells Inspector Campbell that they found Billy Kimber's body, but as there were no police in the area (as per Campbell's orders) there were no witnesses. He also says that because there were no police on the roads Freddie Thorne was able to escape police custody.
Campbell rings Churchill to tell him that he's made a decision about his future.
Thomas visits Grace's apartment and she offers to tell him who she is. He says that he thinks he knows who she is and she knows who he is. She tells him that she loves him and asks him to finish his business there and meet her in London in a week. At the Garrison Pub, Thomas reveals to Polly that because all Kimber's men were busy fighting the Peaky Blinders at Garrison Lane, the Lee family were easily able to take all the pitches at the Worcester Races. Thomas says that the Shelby Brother Limited is the third largest legal racetrack operation in the country, and that only Darby Sabini and Alfred Solomons are bigger than them, hinting at the next series' antagonists.
Thomas writes a letter to Grace telling her he will give her his decision within three days. The ending scene shows Inspector Campbell interrupting Grace at the train station and pointing a gun at her, the sound of a gunshot is audible as the screen cuts to black.
- Tommy threw his medals in the Cut when he came home from France. He used to laugh before he went off to war, and he wanted to work with horses.
- Thomas opens the bottle of champagne that Grace bought him.
- Tommy kills Billy Kimber, ending the brewing war between the Peaky Blinders and the Birmingham Boys.
- Thomas Shelby: “This is the day we replace Billy Kimber. This is the day we become respectable. The day we join the official National Association of Race Course Bookmakers. But first, we do the dirty work.”
- Freddie Thorne: “Holy shit. Danny, you’re dead.”
- Danny Whizz-Bang: “Nah, I’ve been living in London. Same thing.”
- Thomas Shelby: "Next family meeting, I'll make sure you're there."
- Grace Burgess: "If I were family, but I'm not."
- Thomas Shelby: "That could change."
- Grace Burgess: "Tommy--"
- Thomas Shelby: "We'll talk about it more when I get back. All right?"
- Thomas Shelby: “Oh, is this how it’s going to be, eh? You waiting at home for me, saying, ‘What time do you call this?’”
- Polly Shelby: “What’s going on?”
- Thomas Shelby: “We’ve been fucking betrayed.”
- Polly Shelby: “There’s only one thing can blind a man as smart as you, Tommy. Love. It was that barmaid. I’ll deal with Grace. If you set eyes on her again, you might kill her.”
- Polly Shelby: “I feel sorry for you. Slip of a thing. Thought you’d come in here and stitch us all up. I mean, we’ve had some coppers narcs in here but you? You’re the queen of them all.”
- Thomas Shelby: “The past is not my concern. The future is no longer my concern, either.”
- Henry: “What is your concern, Tommy?”
- Thomas Shelby:“The one minute. The soldier’s minute. In a battle, that’s all you get. One minute of everything at once. And anything before is nothing. Everything after, nothing. Nothing compared to that one minute.”
- Henry: “Didn’t you get enough minutes over there?”
- Thomas Shelby:“Seems not, doesn’t it?”
- Thomas Shelby:"Someday I'll throw this gun in the canal."
- Grace Burgess:"Why not now? Here it comes, Tommy. I love you."
- Thomas Shelby:"And there it goes, Grace. Away it goes. We can say it as much as we like... but there is no chance."
- Thomas Shelby: “Without a secretary, I write my own letters, and I write without malice. I learnt long ago to hate my enemies. But I’ve never loved one before.”
- Thomas Shelby (in letter to Grace Burgess): “Before the war, when I had an important decision to make, I used to flip a coin. Perhaps that is what I will do again. Polly tells me you fell in love for real, and Polly is never wrong about matters of the heart. I will give you my decision within three days. All my love. Thomas Shelby.”