Fathers Day

The episode opens with a flashback of Jackie telling a younger Rose about her father Pete, who died on 7 November 1987, the day their friends Stuart Hoskins and Sarah Clarke got married. She tells Rose that no one was around when Pete died after being run over by a hit-and-run driver.
In the present on the TARDIS, Rose asks the Doctor if they can go back to the day her father died so that she can be there when it happens. The Doctor agrees, but cautions Rose to avoid interfering. They watch as Pete, attempting to retrieve a fallen gift for the wedding, is struck by a hit-and-run driver. Rose is unable to move when the Doctor tells her to go and be with her dad, and Pete soon dies. After Rose recovers, she asks the Doctor if she can try again with the time machine. The Doctor, against his judgement, allows for it, but warns Rose to not run until their former selves have left to prevent a paradox. As the accident is able to happen, Rose runs out and pushes Pete aside, saving his life, but causing their former selves to vanish. The Doctor angrily warns Rose about the damage to the timeline but Rose dismisses it, believing Pete to just be an average person. While Rose goes with Pete to the wedding, the Doctor storms back to the TARDIS, only to find that it is now an empty shell and realizes something is very wrong. Elsewhere, strange flying beasts start appearing and consuming people below without warning.
As Rose and Pete drive to the wedding, there is anachronistic hip-hop music ("Don't Mug Yourself" by The Streets) playing on Pete's radio, and Rose gets a unidentified voice message on her phone, "Watson, come here, I need you." At the church, the same car that nearly ran Pete over appears and threatens to run over Pete, but he dodges it, and the car disappears again. As they mill with the guests, including Jackie who has brought the infant Rose with her, young Mickey Smith runs up to the party and warns that all his friends were taken by beasts. As the same time, the Doctor reaches the church and warns everyone inside just as a one of the flying beasts appears and attacks the party. With the surviving members safely in the church, the Doctor explains to Rose that her actions have caused a time paradox, which the Time Lords, if they were still around, would be able to fix; instead, the flying creatures are like bacteria, sterilizing the wound in time by consuming everything inside it, though the age of the church will protect them. As they talk, the key to the TARDIS starts glowing and heating up, and the Doctor realizes that he can summon it and use it to fix the problem, but warns everyone to not touch it until the process is complete. The Doctor also warns Rose not to touch her younger self, as this will further damage the time stream.
As they wait for the TARDIS to fully reappear, Pete overhears the Doctor and Rose talking, and realize that Rose is his daughter. When he approaches her and asks her about how good a father he is, Rose is unable to answer truthfully. Jackie, seeing Pete talk to Rose, believes Pete is having an affair with her, but in order to show that Rose is really their daughter, he thrusts the infant Rose into Rose's arms. As the Doctor warned, this causes a paradox that allows one of the beasts to appear in the church. The Doctor, as the oldest being there, sacrifices himself as the beast rushes to the crowd, causing it, the Doctor, and the faint TARDIS image to disappear, leaving the TARDIS key cold. As the group tries to figure out what to do next, Pete watches the same car that tried to run him over appear and disappear over and over again. He comes to the conclusion that he was meant to die by that car, and determines that by letting himself die, the timeline will be repaired. He has an emotional goodbye with Jackie and Rose, and then runs out to face the car the next time it appears. Pete is fatally struck by the car, but in that instant, the timeline is restored: all those consumed by the beasts reappear, including the Doctor, while the others, save for Rose and Pete, are unaware of the events. Rose runs to Pete's side and quietly stays with him until he dies. Rose returns to the Doctor, and the two walk hand-in-hand back to the restored TARDIS.
The episode ends on a similar flashback as the opener, as Jackie explains to a young Rose that Pete didn't die alone - a young woman stayed with him until he died, leading the adult Rose to eulogise about Pete Tyler, her father, "the most wonderful man in the world."