When Magnussen spoke about wanting to own Mycroft he didn't mean figuratively.
People don't say no to Charles Augustus Magnussen, he can have anyone he wants. In fact, there's only one person with enough power and influence to be out of reach.
Naturally, he's obsessed.
He's been waiting years for this moment, to have the mighty Iceman at his mercy... to fuck him, to debase him. Oh, the things he's going to do to Mycroft Holmes..
Bonuses: Magnussen taunting Sherlock about the things he's going to do to Mycroft.
TL;DR: Magnussen doesn't give a fuck about about state secrets.
Magnussen/Mycroft, I own Mycroft Holmes
People don't say no to Charles Augustus Magnussen, he can have anyone he wants. In fact, there's only one person with enough power and influence to be out of reach.
Naturally, he's obsessed.
He's been waiting years for this moment, to have the mighty Iceman at his mercy... to fuck him, to debase him. Oh, the things he's going to do to Mycroft Holmes..
Bonuses: Magnussen taunting Sherlock about the things he's going to do to Mycroft.
TL;DR: Magnussen doesn't give a fuck about about state secrets.
He just wants to see Mycroft Holmes on his knees.