In 1824, Lyme Regis is as tumultuous as the sea that surrounds it. Wealthy holidaymakers dance in the Assembly Rooms whilst the poor riot over the price of bread, scientists do battle with theologists, and amidst it all, one woman is about to make an extraordinary discovery.

When twenty-four-year-old Ada Winters - poor, peculiar and brilliant - uncovers a set of unusual fossils on the cliffs, she believes she has found the answer to her scientific frustrations and her family's financial struggles.

Meanwhile, Doctor Edwin Moyle has come to Dorset in search of the discovery that will place him amongst the greatest geologists of the age. What he finds instead is a strange young woman who seems to hold the key to everything he desires.

But what is the creature that Ada and Edwin seek to unearth? And will it be their means to greatness, or destruction?