In 1983, a tenacious Australian physician named Barry Marshall drank a beaker of bacteria to prove his colleagues wrong — and won a Nobel Prize two decades later for upending everything medicine thought it knew about ulcers. But the real story isn't the dramatic self-experiment: it's why the evidence was sitting in plain sight for years, how the architecture of scientific consensus actively suppressed a correct answer, and what the strange biochemistry of Helicobacter pylori reveals about how living things survive in places they have absolutely no right to exist. Last episode we watched a photograph hold the secret to life's blueprint; this week, the secret was hiding in half the world's stomachs.