Legend says that Horseshoe Bay's most infamous sea queen wore her crown for one night before dying. She is said to haunt the town.
Nancy finds a lost girl when she is young and becomes addicted to solving mysteries. Her mom passes away after she is diagnosed with cancer, causing Nancy to hang up her detective cap forever.
The flashback ends, and Nancy hooks up with Nick and goes to work.
Ryan Hudson and a group of men eat at the diner after closing. Nancy finds his wife, Tiffany, dead outside.
The police bring Nancy and the employees down to the station. The officer reveals that Ned is an ex-convict.
Nancy is questioned and realizes that Tiffany wasn't wearing her ring when she found her. Nancy's dad shows up at the station, but Nancy tells him she doesn't need him and leaves.
After looking at a video she took on her phone earlier, Nancy realizes she has footage of Tiffany being attacked by what looks like a ghost.
Nancy shows the videos to her co-workers and Ace thinks it's the sea queen. Nick comes by and Nancy publicly tells everyone that they're seeing each other.
Nancy breaks into Ryan's house to investigate and takes a necklace and a note from the nightstand. She accidentally sets off a silent alarm and Nick sneaks inside to help her.
On the way home, Nick tries to get Nancy to open up to him and she tells him they shouldn't start anything serious.
George tells Nancy that the necklace is a mariner's good luck charm and the two, along with Bess, go to the ocean to open it. They discover the symbol on the sea queen's crown is inside.
The girls go to see a medium to try and contact Tiffany. The medium tells them to leave when she gets a message from a different ghost instead.
Karen brings the hat Nancy lost at Ryan's to her dad. Nancy walks in on her dad and Karen kissing and storms out of the house. She goes to Nick's and tells him how she feels about him.
Nancy's dad was Nick's lawyer and he warns her to stay away from him. She breaks into her dad's files which show that Nick was charged with manslaughter and Tiffany was the key witness.
Bess is shown living in a van and wearing what appears to be Tiffany's ring.
George goes to Ryan's house and the two appear to have a romantic relationship. Ace takes a picture of them and sends it to the officer on Tiffany's case.
Nancy tries to piece together Tiffany's murder and the lights in her house go out. Nancy goes up to the attack and discovers the sea queen's song written behind the wallpaper in the attic. She sees a bloody dress and a girl appears to be standing behind her.