Earth is teeming with life, and despite these billions of organisms seeming so different -- it turns out that pretty much all life has surprising commonalities science still hasn't figure out. All our molecules follow the same basic 'directions'. And, recently, experts realized it may be possible to 'flip' these directions, and create cells with opposite or mirrored directions. This could provide massive medicinal and research benefits -- yet, as Ben, Matt and Noel learn in tonight's episode, those same experts are increasingly concerned that creating mirror life could also end the world.