Harry Potter and the Pain of Revenge

When Snape caught Harry with his head in that Pensieve, he was furious. Harry didn't run and Snape lost control. When he finds out some new info about TBWL...things change. Now he will protect the boy whether Harry likes it or not. But that doesn't mean Snape has gone soft... Mentor!fic, no slash. Warning: contains physical & emotional abuse and spanking.