The Doctor has successful triggered an explosion aboard an alien battleship approaching Earth. However, he has no way off the ship. Running through the corridors, the Doctor gets to the airlock and spots a spaceship. Another blast takes off part of the ship and the vacuum finally pulls him and the spacesuit out of the ship and down toward Earth. As he falls, the Doctor tries to grab the suit.
At night, Madge Arwell is bicycling down a country road when she hears a screaming man and then an enormous crash. When she goes to investigate, she finds the Doctor, wearing the spacesuit, lying in the middle of a crash crater. When the Doctor yells that he’s blind, Madge points out that he has the suit on backward, including its helmet. She then stops at home and asks her children, Cyril and Lily, where their father Reg is. When they tell her that he’s in the garden, Madge tells them that she’s found a spaceman and takes the car so she can take the Doctor into town to find his police box. As she leaves, Reg comes in and Cyril tells him that Madge has gone to town.
In the nearby town, Madge takes the still-blinded Doctor to the nearest police box. He’s surprised to discover that she can open it with a pin, and then discovers that it’s the town’s actual police box. As he goes to look for his TARDIS, Madge invites him home with her for Christmas. The Doctor says that he doesn’t want to and she tells him that nobody should be alone on Christmas. As he goes, the Doctor tells Madge that if she ever needs help, she should make a wish and he’ll come. Madge returns home and settles down to do her knitting while Reg reads about the coming war.
Three Years Later
Reg is flying a bombing mission over the Channel. When the co-pilot comes up to tell him that the gunner, Anderson, is worried, Reg tells him that they’ll be home for Christmas. As the co-pilot goes back, Reg touches a photo of his wife and apologizes, crying.
Sometime later, Madge wakes up in bed. She looks at the telegram that the government sent her informing her that Reg died on the bombing mission. As Cyril and Lily prepare to evacuate London and go to their Uncle Digby’s manor in the country, they ask their mother if their father will meet them there. Rather than ruin their Christmas, she tells them that he’ll be there.
When the family arrives at the manor in Dorset, no one answers at first. Uncle Digby is in a home on the coast and there’s no sign of the caretaker, Mr. Cardew. When they knock on the door, it’s the Doctor that answers. Madge, having never seen his face in the backward helmet, doesn’t recognize him. He claims that he’s the new caretaker and ushers them in, and then shows them around the place. As they walk around, Madge is surprised to discover that the Doctor knows them all by name without introductions. He shows them all the “improvements” that he’s made to the house, including running lemonade, a sitting room with moving chairs that don’t sit, and a children’s bedroom filled with everything he imagined a child might want. Madge yells at her children when they become interested, and then finally tells the Doctor to stop for a moment and talks to him in private. When she asks why he’s doing so much for them, the Doctor explains that he wants to take care of them. Madge finally admits to him that Reg is dead, and the Doctor realizes that she’s yelling at the children because she can’t bear to see them happy when she knows they’ll be sad when they eventually learn that their father is dead.
The Doctor and Madge go back to the sitting room and find the children, who have found the Doctor’s special Christmas tree. There is also a large blue box containing a present for all of them. The Doctor slips away and Madge warns her children to stay away from him. Cyril asks her to say what she always says for Christmas, and Madge finally and reluctantly tells them that it will be the best Christmas ever. As they go, Cyril looks back at the box because he hears whispering voices in it, calling to him.
That night Cyril and Lily are in their new bedroom, trying to go to sleep. Cyril still hears the voices and suggests that they go down to look at the present, but Lily tells him to go to sleep. Meanwhile, Madge is in her own bed, alone, holding the government telegram.
Lily wakes up a little later, sees Cyril apparently asleep, and hears the sound of the Doctor’s sonic screwdriver. She follows the sound up to the attic and finds the Doctor sitting in front of the TARDIS, doing some rewiring. He claims that the TARDIS is a wardrobe painted like a police box but Lily doesn’t believe him. When the girl asks who he really is, the Doctor avoids the question and asks where Cyril is. Lily goes to check on her brother and confirms that he’s apparently asleep beneath his duvet, and then goes back to tell the Doctor that Cyril is okay.
Cyril has put a teddy bear beneath his duvet and gone down to the sitting room to examine the present. He opens the box and hears the voices calling him to come in. Snow flies out of the box and Cyril looks inside, and finds an entire forest inside of the box. He goes through and enters the forest, and a tree in front of him grows sparkling silver spheres like Christmas ornaments. When he pulls one off, it swells in his hand. Cyril drops it and runs back through the box to the sitting room.
In the attic, a sensor goes off and the Doctor asks Lily if she’s sure that Cyril is asleep.
Cyril finally summons his courage and goes back through the forest. He discovers that the silver sphere has cracked in half and there are footprints leading away from it into the forest. Intrigued, Cyril follows them.
The Doctor checks on Cyril and confirms that he’s snuck out. He runs to the sitting room with Lily and find the open box. The Doctor takes her through, warning her that Cyril has a 20 minute head start because of the time difference between worlds. They follow Cyril’s footprints and the Doctor notices that the footprints that the boy was following grow steadily larger. Lily runs ahead and sees another tree with the silver spheres growing from it. The Doctor hears the same voices that Cyril heard and tells Lily that he’s been there before, but the tree were never so active in the past. When he examines the sphere, the face of a wooden statue appears in it. The Doctor realizes that something is wrong and apologizes to Lily, admitting that Cyril is in danger.
Madge finally checks on the children, discovers that they’re missing, and goes to the sitting room. She sees the open box and the forest beyond.
Cyril follows the footprints to a large tower in the middle of the forest. Inside he finds a large wooden statue of a king, seated on a throne. There seems to be nothing else unusual about it and Cyril climbs the stairs to the top... unaware that the Wooden King behind him has opened its eyes.
As they follow the footprints, the Doctor explains to Lily that the whole thing was intended as a treat for Christmas day, and that the forest world is one of the safest places in the universe. However, they hear something rumbling, shaking the earth, and the Doctor realizes that he might be wrong.
Madge is following the footprints when she feels the same shudders. The foot of a gigantic robot harvester slams down in front of her and a voice tells her to halt, and that she’s on a tree farm. Three soldiers, Droxil, Ven-Garr, and Billis, emerge from a door in the foot and hold Madge at gunpoint. They’re able to get a solid reading on her because she’s wearing wool, which their sensors can’t penetrate. Their leader, Droxil, asks if she knows what’s happening to the forest and Madge breaks into tears, saying that it’s Christmas.
At the top of the tower stairs, Cyril finds a door and goes in. The door closes behind him and he finds himself in a chamber with a statue of a Wooden Queen. As he goes by it, the boy is unaware that it is coming to life behind him.
The Doctor and Lily find and enter the tower, and the Doctor realizes that the Wooden King is what grew from the tree bauble and left the footprints that they followed. He also realizes that the trees grew together to create the tower, apparently as a trap, and wonders what they need people for. Lily hesitates but realizes that they have to go in and find her brother.
The soldiers inform Madge that they’re in the middle of a military engagement and ask her to stop crying. They argue about what to do and Droxil finally has them put down their guns. He explains that they’re from Androzani Major and that they mean Madge no harm. Madge draws her pistol and informs them that there’s a war on, and that she wants her children.
The Doctor and Lily go up the stairs but discover that the door to the upper room is locked. While the Doctor tries to open it, Lily looks out the window and sees thousands of glowing lights rising from the trees. The Doctor looks out and confirms that they’re the life force from the trees, and that they are singing.
The Wooden Queen produces a golden head band and advances on Cyril. As she places it on his head, the Wooden King stands up from his throne in the tower and starts walking up the stairs.
Madge forces Droxil and the others to go aboard the harvester and has Billis tie the others up. While Billis tries to scan for life forms and locate Cyril and Lily, Droxil warns that the company they work for plans to melt down the trees for fuel using acid rain. The rain begins in five minutes and will kill anyone still in the forest.
The door to the upper room opens on its own and the Doctor and Lily go through. They find Cyril, unconscious, and the Doctor asks the Wooden Queen what has happened. She makes no response, and the Wooden King arrives. The two statues advance on the Doctor and, being wood, are immune to his sonic screwdriver. However, the Doctor realizes that they just want to talk. Cyril speaks up, confirming that he can hear the trees speaking to him.
Billis locates the children’s life signs on the scanner. Madge asks them to take the harvester there, but Billis apologizes, saying that she doesn’t know how to pilot it. She establishes an audio connection to the tower and then teleports back to their ship in orbit with Droxil and Ven-Garr.
Cyril tells the Doctor that the “trees” are evacuating because of the coming acid rain, and the Doctor realizes that they need to travel inside of a living thing to make their escape. The crown lets the two tree representatives, the Wooden King and Queen, talk through Cyril and use him as a lifeboat to hold the rest of their kind. The Wooden Queen, speaking through Cyril, tells the Doctor that his coming is foretold. When the Doctor wonders why they can’t leave using Cyril, the tree-creatures admit that he is too weak to sustain them. The Doctor suggests that they use him but they also dismiss him as weak. He refuses to accept that and grabs the head band, but it glows and he screams in agony, unable to let it go. Lily manages to take it from him without harm and the Wooden Queen touches her. It says that Lily is strong, but Lily drops the band and goes to Cyril. Meanwhile, the acid rain begins to fall, covering the windows of the tower.
Madge, still aboard the harvester, can hear her children talking as Lily assures Cyril that their mother will come from them. The Doctor warns that the tower won’t protect them for long but Cyril wants to stay and wait for Madge. The ground shakes and they look outside to see the harvester approaching the tower with Madge in the pilot’s chair. She brings it through the rain to the tower but it falls over at the last moment. The Doctor goes to greet her and Madge comes upstairs to be with her children. The Wooden King and Queen approach her and put the head band/relay on her, and Madge eagerly accepts it.
The Doctor checks the harvester to see if it’s usable and notices the life forces of the trees entering the tower’s top floor. When he runs upstairs he seems them all enter Madge, who stands smiling. She tells the Doctor that she’s perfectly fine, and the Wooden Queen informs them that Madge is strong. The Doctor realizes that he and Cyril are “weak” because they’re males, and while Lily was strong, Madge was the strongest because she’s a female and a mother... and the trees now have a mothership.
The top of the tower lifts off and enters the Time Vortex, and the tree statues tell the Doctor that Madge only needs to think herself and her children back home. The Doctor tells Madge to concentrate and that she has to feel and remember, even if it hurts. She takes the telegram out of her pocket and studies it, and images of her and Reg appear on the tower window: her memories that she’s using to guide them home. However, Madge soon starts thinking of Reg’s death over the Channel and she refuses to remember them. The tower ship starts to twist out of control while Lily and Cyril realize that their father is dead.
Reg is living the last minutes of his life, saying goodbye to the photo of his wife, when a blinding light fills the cloudless sky ahead of him.
The Wooden King and Queen collapse as a burst of light fills the room and then dissipates. The Doctor tells Madge and her children that the forest has transformed into light and gone out into the stars now that they are safe. He looks out the tower window and confirms that they’re back in Dorset outside of the house. The children still want to know about their father and the Doctor suggests that Madge might not want him there. She says that she can’t imagine someone preferring to be alone but asks him to wait outside. She then tells Cyril and Lily that Reg’s plane was damaged over the Channel and it was a cloudy night so he didn’t have any stars to find his way back.
Before Madge can tell them what happened to Reg, the Doctor comes back in and tells them that there’s something they have to see. They follow him outside and the Doctor explains that there was one star that Reg could use to find his way home. Reg saw the burst of light from the forest from the Time Vortex and followed the gap… arriving at the house as well. The bomber has landed on the yard and an astonished Reg is standing next to it. When he asks where he is, Madge tells him that it’s Christmas day and his family runs to embrace him while the Doctor stands apart, smiling.
That night, the Arwells are celebrating Christmas in their temporary home and the Doctor slips away to the attic. Madge follows him and finally realizes that he’s her spaceman from the village. The Doctor explains that since she was there for him, he wanted to be there for her. Madge asks him to stay and celebrate Christmas with them, but the Doctor tries to duck away. She figures that he’s going to visit his family and friends, but the Doctor explains that his family is long gone and his friends think he’s dead. Madge tells him that he can’t torture them like that and orders him to go see them. The Doctor childishly agrees to think about it and prepares to enter the TARDIS. Madge asks him what happens if she needs him again, and the Doctor tells her to make a wish. As the TARDIS dematerializes, Reg comes in and asks what happened. Madge casually tells him that the Doctor has left via the Time Vortex and that she was there as well, and they go downstairs to be with their children.
Amy is at her apartment and answers the door to discover the Doctor at her doorstep. He confirms that it’s been two years since she last saw him, and Amy informs him that River told her and Rory that the Doctor wasn’t dead. Rory comes to the door and they invite the Doctor to share Christmas dinner with them. When he wonders if they have enough food, the couple tells him that they set a place for him each year. As they go inside, the Doctor feels a tear on his face and realizes that he’s crying from happiness.