In 1831, a young amateur scientist, Charles Darwin, embarked on an epic two-year journey, but the journey lasted 5 years and culminated in the discovery of something that would rock the world.
In this parallel universe there are Monster Girls, which led Darwin to come up with a slightly different theory than the one you know.
The story has no commitment to reality, but it is partially faithful. Any resemblance to reality is accidental and disastrous.