A Son's revenge, a Daughter's Love

Snape's father is alive, now Hermione's parents are dead because of it. Snape is forced to babysit our favorite know-it-all for the summer, what's gonna happen? (takes place the summer between 6th and 7th year, eventually 7th year, non DH compliant, AU after 5th Year, rated M for language and because I will eventually get THERE and I won't want to change it then)