Mr and Mrs Smith

In the year 1865, in Bavaria, a rider on a horse arrives outside a wooden shack in a forest. The rider dismounts and, to the surprise of a man waiting outside, enters the building. Inside the man’s wife has just given birth and when the rider removes her hood it is revealed to be The Rani, having recently regenerated (see the end of "The Interstellar Song Contest"). The Rani tells the pair that she is here to take the baby as he is the seventh son, of a seventh son, of a seventh son and so the newborn is the incarnation of Desiderium, a god with the power to make wishes reality. As the baby’s parents object to this, the mother dissolves into flowers while the father is changed into an owl and the other sons into ducks. The Rani then takes the baby boy and departs.

On the 23rd May 2025, The Doctor, living under the name of John Smith, and Belinda Chandra awake in bed together. They appear to be a married couple and are delighted to start another day with their infant daughter, Poppy. As The Doctor prepares to go to work their television shows Conrad promising perfect weather across the world and he wishes everyone a perfect morning. He then begins to read a story about The Doctor and the Time Lords called ‘Doctor Who and the Deadly Wish’. Unbeknown to The Doctor, Conrad is using Desiderium to project his vision of society over Earth in a reality that has been created by The Rani.

As The Doctor is about to leave for work a woman arrives on his doorstep. This is his former travelling companion, Ruby Sunday, who he does not recognise. Ruby, aware that something is wrong with the world, introduces herself and then tries to convince The Doctor that he is not called John Smith and that he does not have a wife and daughter. This offends The Doctor and so Ruby quickly apologises and leaves. In doing so she encounters Melanie Bush, another of The Doctor’s former travelling companion who now lives in the house next door, taking out a dustpan to a bin full of broken mugs. The Doctor follows behind her and tells Melanie to avoid talking to her. As Ruby hurries away The Doctor continues on his way to work, while in the distance Bone Beasts can be seen striding across the landscape. The Doctor arrives at work for UNIT, which in this altered reality stands for the Unified National Insurance Team, that is overseen by Kate Lethbridge-Stewart. The Doctor though starts to doubt things especially when he witnesses a woman fly by outside and questions who she is. When everyone stares at him, he realises that he has said something wrong and quickly apologises. This is The Rani returning to her Bone Palace, which presides over London, and so no explanation is needed as to who she is.

The Rani and Mrs Flood

Back in The Doctor and Belinda’s home, Belinda’s mother and aunt visit and they start talking about Poppy's past. Belinda begins to question her role at being Poppy's mother as she cannot recall the birth of her daughter. Meanwhile, Ruby encounters UNIT's scientific advisor, Shirley Bingham, who now lives in a makeshift camp with other displaced disabled citizens. The group shares with Ruby their awareness of reality's altered state and that none of their lives quite make sense, as if they are not real to the rest of the world, that they have fallen through the cracks.

Upon his return home from work, The Doctor watches Conrad's transmission on the television. But it is disrupted by images of both his granddaughter Susan and Rogue, the latter warning him that the reality he is in is wrong. Rogue convinces The Doctor that in this reality objects can fall through other solid objects. Belinda awakes to the sound of smashing crockery. She witnesses her husband experimenting with the table, mug after mug crashing to the floor as they pass right through the solid table. The Doctor insists that this is not what tables are meant to do - so explaining why so many mugs get smashed. Tearfully, Belinda calls the police, concerned that her husband has doubts and because expressing doubts is against the law. Mrs Flood, posing as a police officer, quickly arrives and both The Doctor and Belinda are arrested and taken away.

Conrad Clark

The pair are brought to the Bone Palace, where The Rani confronts The Doctor and attempts to jog his memory, saying that they are old acquaintances. Belinda though is in a state of disbelief - insisting that they are married, have a daughter and that she just wants to go home. The Rani though dismisses this as false and begs The Doctor to remember, insisting that they were never truly enemies - as she wanted life, not death. Belinda is forced to leave the Bone Palace while The Rani takes The Doctor to see Conrad and the baby, explaining that despite being a child he is the most powerful god in all of The Pantheon. She then shows The Doctor the Vindicator, the device that he used to return to Earth. The Rani explains that the web of energy it created will amplify the power of Desiderium, allowing for the creation of the whole world and this alternative reality. But even this is still not enough and she explains that as doubts seep through they crack this world and the doubt of a Time Lord has the ability to fracture the whole reality.

The Rani then takes The Doctor out onto a balcony, high above the city, to show him the world outside, a world that is fractured and is tearing itself apart with buildings sinking into cracks. She tells him that by creating this compromised reality it will be destroyed by the people living in the world doubting that reality. This will then allow her to rescue Omega - the creator of the Time Lords - who is imprisoned in the Underverse. As the name echoes throughout his mind, The Doctor finally remembers who he is. But it is too late. It is midnight and on finding himself locked outside he can only watch as more and more buildings collapse all over the city as the date changes to the 24th May. The balcony then crumbles away sending The Doctor spiralling below. Inside the Bone Palace, The Rani and Mrs Flood give a toast to their success.

As The Doctor falls through the air a door suddenly opens up mid-air and Anita Benn, who he befriended while spending a year with her when he was tapped on Earth (see "Joy to the World"), beckons him inside. Via a time-portal she takes him to the Time Hotel where he learns that The Rani has put Earth into a time loop by using a wish from Conrad and Desiderium. The Doctor, with Anita’s help, returns to the house inhabited by him and Belinda in the wish. He takes Belinda to the Time Hotel, shocking her out of the illusion she is in. They then use the Time Hotel's doors to restore the memories of everyone at UNIT, while Ruby Sunday and the other UNIT agents have their memories restored via chip implants. They then make their way to UNIT headquarters. As does Melanie Bush.

Mr Smith and Melanie Bush

The Rani, using Conrad, locates The Doctor in the UNIT headquarters and teleports there to confront him. The Rani explains how she survived the destruction of the Time Lords and has been following The Doctor, noting for Ruby and Belinda that she is Mrs Flood as well. She then reveals her plan to bring Omega into the universe and to use his biological material to create a new race of Time Lords under her rule. The Doctor objects to this stating that Omega is mad and was sentenced to the Underverse for a reason. After Melanie suggests that the two of them could just repopulate the race instead, The Doctor informs her that this is not possible as the Time Lords are sterile, which is why his daughter, Poppy, is so special. The Rani then teleports away, returning to the Bone Palace. There she turns the Bone Beasts onto UNIT headquarters. As UNIT scrambles to defend themselves, The Doctor has Belinda take Poppy into a special chamber, the zero room, to prevent Poppy being erased once reality is restored to normal as their daughter was only created in this altered reality.

UNIT fits Ruby out with a personal transmat device, that she uses to teleport directly to the room where Conrad is, while The Doctor uses The Rani's hovercraft to enter the Bone Palace, piercing its protection. He discovers that The Rani and Mrs Flood have managed to fix a lock on Omega's location in the Underverse and are in the process of retrieving him. But, as The Doctor predicted, his time in the Underverse has changed him into a massive, skeletal monstrosity. Omega states he intends to consume all and seizes The Rani, devouring her. Mrs Flood takes the time ring the pair were using and takes off, leaving The Doctor to confront Omega alone. The Doctor grabs the Vindicator off the wall, and fires it at Omega, forcing him back through the portal that then closes sealing him in the Underverse once more. Meanwhile, Ruby picks up Desiderium and wishes Conrad to be happy in a new life and for his wish to be undone. In doing so Conrad vanishes and Ruby, with Desiderium, find themselves in the TARDIS. The Doctor arrives and makes a wish for Desiderium to no longer grant wishes.

The TARDIS returns back at UNIT Headquarters. The Doctor makes a quick exit and heads straight to the zero room. He is relieved to discover that both Belinda and Poppy are safe. The Doctor then takes Desiderium to Ruby's family, so that Carla Sunday can look after the infant, and Anita departs for the Time Hotel. Back in the TARDIS, Belinda and The Doctor set up a cot in the TARDIS for Poppy, Ruby watching on, the pair planning their adventures, now as a trio. But as Ruby watches them, she sees Poppy vanish and The Doctor and Belinda forget all about her. Returning to UNIT Headquarters, now finally the 24th May 2025, nobody else can remember Poppy either. Despite Ruby’s insistence of Poppy’s existence, The Doctor insists that it is Ruby who is mistaken. Ruby though eventually convinces everyone that she is correct when she reminds him of how he saved her as a baby as well.

In an effort to restore Poppy, The Doctor departs in the TARDIS, heading into the Time Vortex to carry out a shift in time by a single degree back to a world with one person more in it. As he prepares to set this in motion, the Thirteenth Doctor appears. She tries to talk him out of it, but she quickly relents, and instead helps him with the calculations needed. When she departs The Doctor unleashes regeneration energy into the Time Vortex to trigger the shift in the timeline. But when the TARDIS takes him to Belinda's home he discovers that Poppy is just Belinda's daughter now and Belinda has always been trying to return home to her daughter, ever since she was abducted by robots (see "The Robot Revolution"). After bidding Belinda farewell, allowing her to continue her life as a mother and a nurse, The Doctor departs to undergo his next regeneration in the presence of the star of Joy (see "Joy to the World"), appearing to take on a new incarnation resembling former companion Rose Tyler.