At the end, the main character finds a photo album or birth certificate in her aunt's room... Spoiler ahead.

[Amanda]

I can’t remember the exact plot (or any of it) but towards the end the main character finds a photo album or birth certificate in her aunt’s room that shows the aunt is actually the mother of her dad or mom. Sorry I don’t have more but this is bugging me!

[Amanda]

Read it this year- wasn’t an old book

[Kris]

Amanda, I edited your header/title "Older sister turns out to be the mother" to remove the spoiler, then added a spoiler alert.

Feel free to update the header by clicking the small "edit" link after the header. This only works on the full Desktop website - not the Mobile website or app.

[Amanda]

Ok thank you for that! Sorry about that

[Kris]

No worries.