Call Me Mr. Cumberbatch

Teacher x Student relationship story with Benedict Cumberbatch as the teacher (obviously) ;)
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Cassie has always been the good, quiet student. She's never gotten a detention, never gets in any kind of trouble, and all her teachers love her. The only problem is, she is quite the target for bullies.

It's her senior year in High School and there's a new English teacher transferring from London. Every girl in the school has the hots for him...but he only has his eye on one of them. Not only does he become Cassie's English teacher, but her Theater teacher, as well.

Will Mr. Cumberbatch turn this innocent girl into someone completely different? Will their relationship just be a fling, or will it turn into love? But more importantly...will they get caught?
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For characters, I'm thinking Cassie's step-dad--Rob--can be Robert Downey Jr. :D