Contagion

Four medical officers land on the planet Minos, expecting to document a pristine world. Instead they find a colony in quarantine, devastated by a plague the settlers call 'melting sickness' - a disease that reshapes its victims at the genetic level, blurring the line between human and something else. When the team is exposed, they face a terrifying proposition: the infection doesn't just kill, it transforms. Slowly, irrevocably, they become like the very colonists they came to study. MacLean, writing in 1950, asks questions that still cut to the bone: What remains of 'you' when your body becomes alien? When everyone you love would no longer recognize you - would you still be yourself? This is science fiction as identity crisis, where the real horror isn't death but becoming someone else entirely.