The fourth season of American Horror Story starts off with a stunning cold open amidst a quaint farmhouse. After stumbling upon a gruesome crime scene, a milkman makes an even more shocking discovery in a rural home. It’s difficult to remember an episode of AHS in which the camera work is so effective as it is here. “Monsters Among Us,” directed by show creator Ryan Murphy, prefers to keep things hidden off-screen, and rather than show the audience what it is, we instead get a series of gasps, startling sound effects and a series shots that are framed to hide the dark mystery. “Monsters Among Us” keeps viewers guessing until after the spectacular opening credits before it pulls the curtain up on conjoined twins Dot and Bette Tattler. Ever playful, Murphy’s visuals are also concealing, and yet telling.