Bellatrix is an animagus and escapes with Sirius, Harry catches her and decides to keep her for a pet, she decides to raise him into a Lord and Master that she can be proud to follow. Rated M for sex and animagus sex. There is also violence, including towards children and animals. You have been warned. Based on timbarney110's challenge 'loyal pet.'

With the help of James Thurber's "The 13 Clocks," Petunia, a squib, convinces Severus to help her find alternative magical education. He locates the Matirni Traveling Circus (& squib school). She lives happily ever after (and willingly takes in her little sister's orphan. Who happens to be a metamorphmagus. Plotting ensues.) (Multigender!Harry)

We've all heard about the power of Lily's love because it kept her in the line of fire. But why and how did her sacrifice change the situation as much as it did?

How small a sliver of information would it take to totally change the plot of each book?

This is a partial response to the Final Exam challenge in Harry Potter and the Methods of Rationality by Less Wrong. See chapter 113, of that work. One shot.