Mycroft Holmes and Greg Lestrade have a very clear, simple agreement set up. Sex, once a week, with no romantic entanglement and no strings attached. But of course, relationships are never quite that simple. Rules are bent, boundaries are renegotiated, and the end result may well be something that neither of them ever expected to achieve.
The four times Sherlock failed to set up Mycroft and Greg, and the one time he succeeded.
Mycroft Holmes attends all the right events, knows all the right people and wears a suit like a set of armour. If Sherlock is to be believed, he is also the British Government. In his free time, however, he drops the upper class persona and prefers a simple life. When his relationship with DI Lestrade takes a more intimate turn he is unsure of how to share this side of himself.