Flash of Two Worlds gave us the reveal of Harrison Wells on Earth-2, showing he was doing exactly what Harrison Wells had been doing on Earth-1, only without the evil speedster hidden identity thing). He's running STAR Labs, and is a pretty celebrated scientist for the work he's done there. This week, however, ramped things up a bit, as it ended with Wells making his way to Earth-1. How he knows about these breaches is just one of the questions we need answering, although it's not too much of a stretch that he'd have figured them out given he's so intelligent, and there may even be one in his version of STAR Labs. The more pertinent question is why? What reason could Harrison Wells from Earth-2 possibly have on Earth-1, and is he going to know who Barry and the rest of the team are? If so, how will they react to seeing him back (but not)?