Tempest Key, Florida. Arthur Curry aka A.C. is a happy go lucky 20-something dive shop owner who lives on a houseboat next to the coast guard base where his caring adoptive father Lieutenant Tom Curry works. His best friend is Eva, the pretty owner of the local beach bar. It's been exactly 10 years since the tragic unexplained plane crash in which Arthur's mother disappeared without a trace and only young traumatized Arthur was found alive. In the accident, Arthur discovered that he somehow has the ability to breathe underwater which he later turned to good use. However, he's still burdened by survivor's guilt and hopes he'll one day find out what really happened to his mother. After rescuing some dolphins that he suddenly felt the need to rescue from the local Neptune World marine park, Arthur is arrested by the sheriff. The day only gets more unnerving for Arthur when Eva semi-seriously threatens him with eviction and a strange intense man called McCaffery warns him about the ...