Leviathan by C J Austin

A massive earthquake struck the center of Lake Superior altering its freshwater state to that of an ocean triggering an ecological disaster unlike any in recorded history.

Freelance journalists Bec Trustle and Greta Armodt were sent to the Lake to investigate the story behind the rapidly-growing catastrophe only to be met by a horrific tragedy which left Bec as the only survivor.

Instead of retreating back home, she stayed near the Lake to work closely with the scientific community to uncover what was transforming Lake Superior in to a salty sea. When one of the submersibles mysteriously disappeared on a routine run, mounting evidence of an ancient menace spurred them to abandon the underwater science lab.

As the death tolls quickly rose around and across the Lake, Bec and scientists considered ways on how to deal with the "black devil." Unfortunately, all options required them to return to Poseidon, the abandoned underwater laboratory.

Back to its lair.

Would anyone survive?