Survivor, lost boy, and a plan

as merciful as he is (sarcastic), Voldemort decides to spare Lily, but she still stands for him, and the curse still rebound. Lily wakes up in ruins, she finds her husband dead, and her son missing, she goes to Sirius Black for help, and she knows that if she didn't keep their identity, they'll be in grave danger, what are her plans for young Harry?