You and your friends are walking through the woods, to an abandoned shack on the outskirts of town. Upon your arrival, a siren starts howling in the distance. You all know what this means, but you've only ever heard about it in legends.
Immortality is a scientifically engineered vaccine given to infants at birth. However, some parents chose not to have their children vaccinate as it 'isn't natural'. Your parents did not vaccinate you.