Mycroft is back! This is a photo from the Elementary episode "Marchioness."
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Joan gets close to Sherlocks brother on Elementary. "Marchioness" is the seventh episode of the show's second season.
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Elementary Season 2 Episode 7 Quotes

[To Joan and Mycroft] One question, is this going to be an ongoing arrangement. If it is, I will need to plan accordingly. Get it sorted immediately, it's the least you could do.

Sherlock

[To Joan] Oh my God, you had sex with my brother.... Willingly.

Sherlock