Let Those Who Are In Favour With Their Stars (слэш)

During an undercover task as a Muggle Prime Minister's secretarial team staff member, Harry Potter meets Mycroft Holmes, and they somehow slip into a brief, unspoken entanglement. Not quite a romance, not entirely nothing. Just something... The undercover job ends, and months pass. Then the man shows up at Grimmauld Place, looking exactly as Harry remembers: composed to the point of arrogance, with that ever-watchful gaze that misses absolutely nothing.
“I’m living in a world of goldfish,” Mycroft says dryly. Then, as if on second thought, he looks at Harry and something flickers in his eyes. “But,” he adds, “you’re quite an interesting goldfish.”
“Charming,” Harry says flatly. “So I’m more interesting than the average fish. That’s reassuring.”
A faint smirk tugs at Mycroft’s lips. “Don’t be offended. Most of humanity barely qualifies as plankton.”