"But I don't want to go among mad people," Alice remarked.
"Oh, you can't help that," said the Cat: "We're all mad here. I'm mad. You're mad."
"Oh, you can't help that," said the Cat: "We're all mad here. I'm mad. You're mad."

Forgiveness if there's already been a topic about this somewhere else; I'm new to this guild so I'm a bit disoriented. For those who don't know, Lungbarrow is a Seventh Doctor novel by the author Marc Platt. It's set on Gallifrey and delves into the taboo subject of the Doctor's origins; his family, friends, and who he really is.
SPOILERS
It's a very controversial book with fans, some considering it canon (like me) and others who do the same as they do with the McGann TVM and ignoring it from the fandom completely. I'll do a quick run-through of the plot, even though I haven't read the book for a few years; so forgive me if there's a few errors.
Romana, now Lady President of Gallifrey, looks through the files of the Chapterhouses, only to find that the house the Doctor was loomed into was removed completely, with no hints to where it went. It turns out that one of the Doctor's cousins of the house Lungbarrow, Glospin, was behind a whole plot to gain the power of the House for himself; jealous when Quences (the head of the House) favoured the Doctor for his heir even though he was centuries younger and more immature than Glospin.
Glospin decides to get his revenge by regenerating into a copy of the First Doctor on Quences' deathday and murdering the old man. The Doctor disappears from the House (I can't remember exactly why) and Quences was unable to finish his will until the whole family is gathered together again.
Years later, the Doctor returns to the House, only to find that half of the 40+ cousins of Lungbarrow have been driven insane by being stuck in the crumbling House for over 600 years (making the Doctor nearly 800 years old at this point). They live under the rule of Sattrolope, who is the Housekeeper. She convinces them all that Quences is still alive, ready to finish his will when the family is together again. The Doctor has been presumed dead and has been replaced with another cousin called Owis.
Glospin reveals that he's been learning everything he can about the Doctor; and that he knows that he doesn't belong to the family since the DNA is different... or something. It is revealed at the end when the Doctor becomes the new Head of House that he is the reincarnation of the Other, one of the triumvirate who founded Time Lord society along with Rassilon and Omega.

"How do you know I'm mad?" said Alice.
"You must be," said the Cat, "Or you wouldn't have come here."
"You must be," said the Cat, "Or you wouldn't have come here."
