The episode of The Boroughs unfolds as Sam elucidates to his companions the imperative need to rescue the Mother. In a sudden turn of events, Wally contacts Renee, divulging that he has taken a drastic measure—he has kidnapped the Mother! They swiftly reverse course and head back towards the community center.
At the lab, Annaliese is livid with Blaine for his failure to secure the Mother, yet he reassures her that he will recover her.
Simultaneously, Wally wheels the Mother through the crowd during the 75th anniversary celebration, attempting to conceal her identity beneath a shawl and hat. Eventually, he succeeds in bringing the Mother to the community center, where her kin are anxiously awaiting their reunion.
In the town square, Blaine steps forward to deliver his significant speech for the anniversary. Yet, something shifts within him, and he begins to speak about aging and how all things must come to an end.
At the community center, the group deliberates on their next move. Wally proposes utilizing the Mother's blood to eradicate disease and death. However, the Mother communicates with Sam and expresses her desire to pass on. She asserts that her children have been preparing for this moment, and she needs to reach the underground tree. Renee informs Wally that even if he were to live through the Mother's blood, he would no longer be himself. Eventually, he relents.
Now that they are all in agreement, they decide to use the tunnels beneath the oven to escort the Mother to the tree. At this juncture, Blaine and his accomplices arrive. Judy and Art remain behind to delay them while the others descend into the tunnels.
In the tunnels, the Mother points towards her children and declares her intention to rescue them. Paz and Renee resolve to liberate them, while the rest head towards the tree.
Upstairs, Annaliese stabs Judy to coerce Art into revealing their location. He confesses that the others are in the tunnels.
Paz and Renee reach the cages containing the children but lack the key to unlock the control panel. Moreover, Hank is present! Though burnt and battered, he is still alive. However, he does not resist them. Instead, Renee persuades him to take revenge against Blaine by aiding them. He agrees and provides them with the key to the control panel.
Blaine and Annaliese cleverly trapped Sam and his companions by activating metal doors and blocking off the tunnels. Sam soon realized that they were being lured into a trap, but they had no other choice but to take the one passage that was still unblocked. They made their way back to Sam's house, where they prepared for the final stand. Claire informed Sam that she had fixed the issues with his TV particle accelerator, which they could use as a weapon against their enemies.
As Blaine and his people arrived, Wally unlocked the garage doors to reveal an army of TVs. The accelerator worked as intended, trapping Blaine and Annaliese and tearing into them. Annaliese was reduced to light, while Blaine collapsed and fell to the ground.
Attention then shifted to Judy, who was bleeding out. The TVs had fried everyone's phones, making it impossible to call for help. Wally examined her and said she had little time left. She and Art reminisced about their good times until Judy closed her eyes. That's when Mother approached and placed her palm over Judy's wound, healing her instantly. Judy woke up!
Mother asked Sam to take her to the cave but insisted that he go alone. He bid everyone a tearful goodbye and drove Mother to the cave. Unfortunately, we then saw that Blaine wasn't dead yet. By the time Sam got Mother to the cave, Blaine was already there and attacked him. Sam realized that Mother was about to blow herself up and held Blaine down, telling her to go ahead. She gathered her children around her and exploded in a magnificent display of light and energy.
Sam woke up in his final memory with Lily, but this time it was real. Lily said it was Mother's way of saying thank you. They shared one last dance together, filled with love and gratitude.
Sam awoke in the cave to see the dead bodies of Blaine and Mother around him. Renee and Paz arrived there and helped him up. He said that Mother was now at peace. The Boroughs ended with the group all together again, healthy and happy.
Sam, Claire, and their friends had dinner together, celebrating their victory. Paz and Renee had planned a big trip to Europe, and Judy and Art were getting along once again. While Sam fixed his head injury in the bathroom, his reflection in the mirror began to glitch. The episode ended with a final view of The Boroughs, leaving viewers with a sense of wonder and mystery about the cause of the glitching reflection.
Our interpretation is that Mother used her magic to intentionally save Sam from her explosion, which is why he now has a strange, otherworldly quality that causes his reflection to glitch.
