Ivy Potter and the Sorcerer's Stone

Ivy Potter was born to the Potter family the same day her twin brother, Harry Potter, was. Separated at a year old, Harry off to the Dursleys, Ivy was found by the Grangers, a muggle family. When Hermione Granger gets a Hogwarts letter, so does Ivy. She sees Harry, and recognizes him barely, but when the sorting hat and her letter call her Ivy Potter, she knows there's something off. But will they ever discover the truth? What houses will they be sorted into? And perhaps most importantly, what's up with the strange package Harry keeps talking about?

Also if there are continuity breaks, sorry not sorry, 'k? This is an alternate universe so I give no fucks.