No one's fool

What happens when Severus Snape finds out that one of Voldemort's most trusted death eaters is not only a spy for the Order but is also his brilliant pupil, Herimone Granger. Can he support her after being sold out or will he have to enlist help from Draco Malfoy, pureblood boy being pushed to take the dark mark. (DMx HG and slight bromance SSxHG) Rated M loosely to be safe.