Basically, the characters all that go to Hogwarts, and are being plagued by their inner demons, Richard still has AIDS and Clarissa is in a terrible state, Louis is suffering because he cannot get away from the guilt of what happened to Richard.
Meanwhile, in another timeline, Virginia Woolf is fighting against the Daleks with her sonic quill pen and she doesn't realise that the damage she is doing to the modern Hogwartion timeline involving Clarissa and Richard.
In the third timeline is Laura Brown, ex-demon hunter now tied down to domestication, she is visited by a blue police box and becomes Virginia's companion, until the two realise she is pregnant. Laura is then left back in the 1950's, the time from which she came, haunted by the memories of her time with Virginia. She tells the story to the baby in her womb and leaves him as soon as he is born.
Back on Clarissa's end, she watches as Richard stands atop of one of the towers of Hogwarts, as he contemplates the meaning, the mere reason for his life. And he jumps But as he's falling, he is caught, by a woman on a broom, who flies him to a familiar blue telephone box
Virginia, the time lord realised that Richard was the key to getting back to Laura Brown
And then come the paradoxes One after another after another, more and more time paradoxes as Virginia uses Richard to unite with her former companion. And in the end, Virginia has to let the insignificant Laura go.
But how is Laura? Laura sits in her nursing home, rocking on a chair, dumbstruck as she sees who she thinks is Virginia Woolf.
"It's time to take your medicine Mrs Brown".