The Properties of Lightning

There's a heatwave in London, but it's not affecting Sherlock. Oh no. Any more than he's being affected by his new flatmates- John, Mary, Molly Hooper and Molly Hooper's unconscionably teensy pyjamas. (Seriously? Are they even legal?) But as the heatwave rolls on and Molly and Sherlock get closer, might the Great Detective finally lose his cool? Rated hard T