Love's Sacrifice

What if Snape saw Lily's daughter and not James Potter's son? Holly Potter, who has a fierce heart and burning desire to save those she loves. Severus, the darkly sacrificial man who has nothing but loyalty left to give. Or does he have more? The one he shouldn't love, does he save her from death or does she lead him to a fate worse than what he already has? AU. Begins Ootp.