The episode opens in Odessa, Texas on June 13th, exactly one year in the past. Hiro and Noah walk into the Unity Summit. Noah briefs Hiro on what he knows about the Summit. He knows his daughter died at a hospital sometime after the summit and he also knows that the Unity Summit was destroyed by six different bombs. Noah asks if they could just call in a bomb threat, but Hiro warns him that it would be too risky and that they need to find the path that causes the least amount of wrinkles in the timestream. A Renautas employee (Stevens, the bald security guard Noah found dying in Primatech’s headquarters earlier this season) approaches Noah and tells him that Claire arrived at the Summit early. As Noah and Hiro begin to look for Claire, a car pulls up and Noah (the one from the past) steps out, smiling and full of hope.
On the outskirts of town, an SUV pulls up to a man standing on the side of the road. It’s Mohinder Suresh. The window rolls down, revealing Angela Petrelli. After Mohinder gets in the car, Angela warns Mohinder that trusting Erica was a mistake. Mohinder protests, pointing out that Renautas has funded Mohinder’s research for years. Angela reveals that she knows about the upcoming magnetic pole shift and pulls out a copy of Mohinder’s manuscript as proof. While Mohinder thinks Erica will help stop the upcoming solar flare, Angela warns him that Erica plans to just let the solar flare wipe out humanity. Mohinder’s research proves that the evos can stop the solar flare, but Angela says that Erica has ulterior motives. Erica knew about the solar flare because of one of Angela’s visions, which showed both the solar flare’s approach and the evos who could save the world. Angela wants to go to the press, but Mohinder says he’s already going to reveal the solar flare’s existence today at the Unity Summit on Erica’s behalf. Angela predicts that Erica will betray Mohinder, but Mohinder doesn’t listen and gets out of the car. As Mohinder leaves, Angela gets a phone call. It’s someone calling from Claire’s phone.
In the suburbs of Odessa, Erica approaches a nondescript home that’s actually a Renautas holding cell. Richard is monitoring Phoebe, who’s struggling to control her powers in a special cell. Erica tells Phoebe that she needs to create enough shadow to cover the entire Unity Summit and says that if she fails, Erica won’t save Phoebe’s brother Quentin from the upcoming solar flare.
In a hotel room, Luke’s son, Dennis, plays with the toy boat he built with his father. As he approaches the window, a ray of sunlight causes his arm to burn. Luke tells Joanne and Dennis to come to the Summit with them, hoping to meet an Evo who can cure his son’s condition.
Past Noah runs into a very confused Stevens, who doesn’t understand why Noah changed his clothes. After telling Noah (again) that Claire’s at the summit, Noah asks why there’s no security in one of the parking garages. Stevens explains that Erica had changed the security detail, causing Noah to grow suspicious of the Renautas CEO, who has just arrived at the Summit.
In Japan, past Hiro is sitting at a desk when Otomo, the creator of Evernow, walks into his office. Otomo says that he’s designed a world that could save all of humanity from the solar flare, but only Hiro’s time traveling powers can safely transport people inside of it. Otomo begs Hiro to assist Erica with her plan, but Hiro tells Otomo that he’s Erica’s partner, not her employee. When Hiro refuses, Otomo uses his powers to teleport Hiro inside Evernow, trapping him inside the game. He steals Hiro’s sword and rushes outside of the room. Meanwhile, (past) Noah calls Hiro’s phone, but it’s too late to warn him.
Future Noah and Hiro enter Noah’s old Primatech office, hoping to find Claire. After Noah briefly explains their plans, they hear someone approach. Noah takes Hiro inside a secret room, just before Past Noah and Erica enter the office. Past Noah confronts Erica about the change in security detail, but Erica brushes him off. Erica goes on a ramble about how evolution is only good when controlled, before detaining Past Noah to prevent him from interfering with her plans. Future Noah and Hiro start to follow Past Noah, but they’re interrupted by Angela, who tells them that Claire’s in surgery at a nearby hospital. Hiro tells Noah to “save the cheerleader” while he stops the bomb.
Noah and Angela arrive at the hospital, but it’s too late. A nurse says they did everything they could, but they could only save Claire’s children. It seems that Claire was pregnant and died in childbirth.
Mohinder arrives at the Summit and tries getting in touch with his research team, who Angela said were killed by Erica’s men that morning. He sees Molly Walker and gives her a copy of their manuscript, just before Harris takes him to see Erica. Erica tells Mohinder that there’s been a change in plans, leading Mohinder to confront her about the murder of his team. Harris shoots Mohinder with a tranquilizer dart and drags him away to the (unsecured) parking garage.
At the hospital, Noah is in the nursery trying to think of a way to kickstart Claire’s regenerative abilities. Angela tells him that Claire’s children are important and that she had a vision about them, but she’s cut off by the arrival of Claire’s doctor, followed by a nurse carrying Claire’s twins. Noah holds one of the babies for a moment and says he needs to see Claire one last time.
In the parking garage, Harris has Mohinder tied up, saying that he’ll be blamed for the upcoming explosion. Harris is interrupted by future Hiro, who draws two swords. As they begin to fight, Harris reveals that he has the bomb strapped to his body, but Hiro stops him by cutting off his arms and running him through with both swords. Unfortunately, Harris’s body dissolves, revealing he was a clone. Mohinder frees Hiro before several more Harris clones appear. Mohinder chases one through the parking garage while Hiro briefly fights two other clones before deciding to teleport away to prevent a disruption in the timestream.
Luke, Joanne and Dennis arrive at the Summit. Joanne eyes some protestors and says she wants to leave, but Luke convinces her to stay.
In Primatech’s headquarters, the man with the bow tie enters the room where Past Noah is imprisoned. While Noah originally thinks the man (whose name is Casper) has turned on Noah and the Evos, Casper subtly reveals that he’s there to help him escape. Casper then “drops” one of his pennies. The security guard picks the penny up, causing both Noah and Casper to smile.
At the hospital, Future Noah enters the room where Claire’s body is being stored. Noah apologizes to his daughter for not protecting her and then vows to keep her children safe. Hiro teleports into the room and says that he couldn’t save the summit. He explains that every time he tried to stop the bombs from going off, the consequences in the future were far worse. Hiro and Noah try to teleport away, but Hiro can’t use his powers as a shadow has descended upon the entire town. Phoebe has mastered her shadow abilities, causing everyone’s powers to turn off. At the Summit, Dennis loses a balloon as everyone else looks up into the sky. Meanwhile, Past Noah and Casper leave Primatech just in time to see the sun get covered in darkness. Past Noah grabs a gun and starts firing it to cause people to flee, just as Luke and Joanne realize their son is missing. While Past Noah’s warning saves a few people’s lives, several of the Harris bombs explode, causing the Summit to go up in flames.
In the aftermath of the explosion, Molly Walker meets Past Noah and Casper in the rubble. At the hospital, Angela tells Future Noah they need to focus on the future, by saving Claire’s children, who are the key to stopping Erica’s plan. Noah realizes that he had his memories erased to protect Claire’s children and Angela realizes that he’s talking to a Noah from the future.
At the Summit, Luke looks for Dennis in the rubble. Luke saves the Evo who Dennis was spending time with, but the Evo hasn’t seen Dennis since the explosion.
Meanwhile, Future Noah realizes the best way to protect the twins is to send them fifteen years into the past, as Erica will be looking for two babies, not two teenagers. The extra time will allow the twins to develop their powers and give them more time to prepare to save the world. Angela offers to go back in time with the twins to protect them. Before Angela and Hiro teleport away, Noah and Angela name the twins Nathan, after Angela’s dead son and Melina, after Noah’s mother. Before leaving, Hiro warns Noah not to step on any more butterflies.
As Future Noah watches victims file into the hospital, he sees Erica denouncing the attackers on television. He decides that killing Erica is “fate” and storms off to confront the Renautas CEO, who has just arrived at the hospital Meanwhile, past Noah enters the hospital and asks Molly to find Claire. Molly uses her powers, but can’t find her and realizes she’s dead. Past Noah sees Future Noah walking by at the hospital, following Erica walks down an empty hallway. The episode ends with Future Noah training his gun at the unsuspecting Erica, but Past Noah rushes towards him, shouting for him to stop.