The Doctor tells everyone to jump and fires at the bottom of the Byzantium
. When they look up, they discover that they are now on the bottom of the ship. When they jumped, they "fell" up into the ship's gravity field and ended up upside down on the bottom. The Angels below look more like Angels, and the Doctor explains that they're feeding on the radiation from the crash. Within an hour, they'll be an army. The Doctor opens the bottom hatch and gets everyone inside as the power flickers as the Angels drain the power. Everyone gets inside and the Doctor closes the hatch, but a bulkhead seals them off in the corridor. The Angels breach the hull and advance between light flickers. The Doctor warns everyone not to look at the Angels' eyes, and then locks off the light grid.
The Doctor determines he can open the door, but he'll have to reroute the power from the lights. Octavian asks River if she trusts the Doctor, and she insists that she trusts her. As the Doctor goes back to work, Octavian warns River that if he can't trust the Doctor, he'll tell him about River's secret. He then has his men prepare to open fire once the lights go off. The Doctor begins opening the door and the Angels advance between bursts of rifle flash. Amy and the Doctor get the door open and everyone gets through. After the Doctor closes the door behind them, they get to the secondary control room. Octavian magnetizes the door, but the Angels start to override. The Doctor warns they have five minutes, and realizes that the crew needed air. He opens a concealed panel, revealing the ship's oxygen forest dome. Amy starts counting, but starts from nine rather than five. When she says "seven," the Doctor begins staring at her intently.
Angel Bob contacts the Doctor via radio and asks what they hope to achieve. He warns that the Angels will soon have enough power to consume the ship, the planet, and all the stars. As he talks, Amy says "six." The Doctor demands to know what the Angels have done to Amy, and Angel Bob tells him that the Angels are in Amy's eye. Amy wonders what Angel Bob is talking about, and says she's "five." They realize she's counting down from ten, and Angel Bob says they'll take Amy and then all of them. It says that there is plenty of power on the ship to meet the Angels' aims. A screeching noise bursts out Angel Bob tells them that the Angels are laughing because the Doctor hasn't noticed. As he looks around, a time crack appears in the wall behind them. The Byzantium
shakes and the Doctor tells them to leave through the forest dome while he scans the crack. When he turns around, the Angels have entered the control room and are moving in on him and are frozen only a few feet away. The Doctor tries to get past them without taking his eyes off of them, but one of them grabs him.
The others make their way through the woods, but Amy suddenly comes to a halt.
The Doctor realizes that the Angels are distracted by the crack, and can't feed on the pure time energy. He slips out of his coat and runs after the others.
Amy sits down and clutches at her head, and River uses a med scanner to determine what is happening. When Octavian insists that they should go, River says that they need to wait for the Doctor, and will never forgive herself if he dies. The Doctor comes up behind them, and explains that the crack means the end of the universe. He tells Amy that she's dying and tries to work out what happened. The Angels approach while the Doctor realizes that the Angels can get into a viewer's mind. Amy says "three" and warns that it's coming.
The Doctor contacts Angel Bob, who says the Angels are making Amy count to frighten her, and for fun. As Amy's life functions stop, the Doctor realizes they have to shut out the "screen" of Amy's eyes before the Angel climbs out. He tells Amy to close her eyes and she obeys. Her life functions stabilize but the Doctor warns her that if she opens her eyes, she'll die. All they've done is delay the Angel. The Doctor tells Octavian and his men to stay and guard Amy while he and River go to find the primary flight deck, stabilize the wreckage, and cure Amy. Octavian insists on coming with them and staying with River. He explains that they're engaged, in a manner of speaking. The Doctor agrees and Octavian leaves Marco in command. As they go, the Doctor assures Amy that he'll be back and asks her to trust him. He admits he doesn't know how the crack from her bedroom wall can be there now. As he goes, the Doctor tells her to remember what he told her when she was seven.
As they move through the forest, the Doctor examines the readings from the crack and explains that he thinks there will be a moment when everything in the universe cracks in an enormous bang. Octavian finally explains that he released River from a prison cell and she needs to earn her pardon. The Doctor is more concerned about the day when the crack begins: the year 2010, Amy's time.
The blind Amy asks Marco and the other soldier, Pedro, what's happening. The Angels rip apart the trees, taking out the lights within.
The Doctor, Octavian, and River find a hatch to the primary flight deck, but are unable to open. When River comments that time is running out, the Doctor wonders if it is literally possible. Octavian finally gets the hatch open.
The Angels move in between light flickers and the soldiers prepare to fire. Suddenly a bright light flashes through the forest. The Angels leave and the soldiers determine that the Angels are running from something. Two of the soldiers go to investigate the light.
The Doctor tries to work out why there were no ducks in the duck pond in Amy's village, and why she doesn't remember the Daleks invading Earth.
The soldiers report that the light is a curtain of energy. Amy insists on opening her eyes for a split second to see the light. She looks and sees what appears to be the crack, in the same shape as the crack in her bedroom wall. She wonders if it's following her. The soldiers cover her eyes, and one of the soldiers, Pedro, goes to investigate. Amy asks what happened to the first two soldiers, and Marco doesn't remember sending anyone else. He doesn't remember the other two soldiers, Crispin and Phillip, and Amy tries to explain that something happened. Then he doesn't remember sending Pedro.
The Doctor realizes that no one remembered the Cyber-king attacking London in the 19th century. Octavian insists that they have to go, and the lights flicker. An Angel grabs him before freezing, and Octavian warns the Doctor that he has to leave him.
Marco goes to take a closer look at the light and gives Amy a spare communicator. She warns him that he'll disappear like the others but he ignores her and moves toward the crack.
Octavian tells the Doctor that he can't trust River, and he doesn't understand who she is. He finally explains that River killed a good man, but tells the Doctor to leave before the other Angels arrive. The Doctor has no choice but to go, and Octavian assures him that he'll die content. The Doctor goes through the hatch to where River has found a teleporter, but the Doctor warns that it's useless.
Amy contacts Marco on the communicator as he approaches the crack. He describes approaching it, and then his radio goes dead. The Doctor contacts her and she tells him what happened, and he admits that he shouldn't have left her there. He tells her to use the radio to home in on his sonic screwdriver and she makes her way through the forest, As she moves, the Doctor explains that time energy is spilling out of the crack, and if it catches up to her, she'll be wiped from existence.
As Amy makes her way through the forest, the Doctor sends software for a proximity detector to her communicator. He explains that the forest is full of Angels, and she'll have to walk like she can see. As he works, River wonders how they can stop the crack, and the Doctor explains that feeding it a large space-time event will delay it. When River wonders what they have that could do that, the Doctor angrily says that he'll have to sacrifice himself.
Amy's communicator detects Angels all around her. The Doctor tells her that the Angels are scared, and that they will instinctively freeze upon assuming that Amy can see them. She has to walk as if she can see. Amy finally continues, avoiding the angels with the communicator. At one point she trips and drops the communicator, and the Angels start moving toward her. Unable to get the communicator, she stands up, the Angels reach for her, and... River teleports her to the flight deck.
Alarms go off as the Angels drain the last of the ship's power. The shield releases, revealing the Angels amassed outside. Angel Bob is there and tells them that the time field will destroy all of reality. The Angels want the Doctor to save them and his friends by throwing himself into the craft. River volunteers herself, but the Doctor notes that her power isn't sufficient, and even the Angels' combined power would barely equal his own. The Doctor tells her to get a grip, literally, and then informs the Angels that they've forgotten the gravity of the situation. The Doctor turns off the gravity as he, River, and Amy, hang onto the walls. The Angels "fall" into the crack, and their combined energy closes it.
The trio makes their way back to the TARDIS. The Doctor explains that the memory of the Angels was wiped out, meaning the Angel is no longer in her memory. She still remembers because she's a time traveler. He warns her that the crack is gone, but the explosion that caused it is still happening, somewhere in time. The Doctor then talks to River, who is in handcuffs and waiting to be taken back by the surviving Church soldiers. She suggests she might have done enough to do a pardon, and the Doctor asks her about what Octavian said. River admits she killed a very good man, the best man she's ever known, but says he'll have to live the story. However, she warns him that they will meet again quite soon, when the Pandorica opens. The Doctor dismisses it as a fairy tale, but River only laughs. Amy says goodbye to her as she teleports away.
As they enter the TARDIS, Amy asks to go home so she can show him something, and explains that she's running from something. They go to her bedroom, five minutes after they left, and she shows him her wedding dress and her engagement ring. When the Doctor wonders who, she explains that it's Rory and she went with the Doctor because she needed comforting. When she talks about who she wants, the Doctor has no idea what she means. Amy tries to kiss him and the Doctor insists it can never work. He notes she's getting married in the morning, and says it's all about her. The Doctor says that she's the most important thing in the universe and hauls her into the TARDIS. The Doctor looks back at her clock, and sees the time go to the day that he determined as the source of the explosion.