I have the biggest weakness for horror/thriller books about the ocean. I immediately had to pick this up. 

Five friends go on one final scuba dive in Australia before they head off to college where they find a hidden cave. Of course they have to explore and after they return to shore, they start to notice strange changes. Later on the friends are taken as ransom by treasure hunters in an effort to gain knowledge on the location of this cave.

This was an entertaining read and had me curious about what was happening to them internally. I was less interested in the treasure hunter aspect of this story though. It reminded me a bit of the Outer Banks show. This story alternates between the past and present day. At times it felt a bit slow but I loved the urban legend feel that this had. 

Thank you to NetGalley and the publisher for the arc!