On the day of the accident, I lay in a pool of blood and felt relieved.   My phone was still showing Mom's message.   Mom: You're the reason your sister fell down the stairs when you were children. You cost her the use of both legs. You could spend your whole life paying her back and still owe her.   When I was 8, my sister, Erica Sutton, tried to snatch my doll. In the scuffle, she missed a step and tumbled down the stairs.   When she woke up, Mom pointed at me and said, "We found you abandoned. You should be grateful we were willing to raise you at all."   After that, I learned to give in.   When Erica needed a new wheelchair, I gave up my college plans and worked three jobs to pay for it.   When the man she wanted to marry fell for me, I quit my job and left the city.   Then came Christmas last week.   I stood outside the door with Christmas cookies in my hands and heard Dad ask quietly, "Have we been too hard on Natalie? She's our biological daughter too."   Mom sighed. "We can't treat them both equally. If we hadn't told her we found her abandoned, how else could we make sure she'd spend her whole life giving in to Erica?"   The Christmas cookies slipped from my hands and shattered across the floor.   Just before I lost consciousness, a second message arrived from Mom.   Mom: Erica needs surgery. Come home and pay for it.