Previously on Nancy Drew Season 3, Temperance cursed Nancy and Ace. If Nancy ever reciprocates Ace's feelings, Ace will die. So Nancy tells him she doesn't share his feelings, and she never will.

A mysterious caller asks Nancy to meet him at the cemetery at 10 pm. When she gets there, she finds eight empty graves.

Five weeks later, Nancy hasn't solved the case but has a nightmare that a reanimated body attacks her and drags her into a grave. She's also taken on small-time cases, like looking for a missing ferret, to pay the bills on her new business, Nancy Drew Investigations and Icarus Hall, which was left to her by Temperance.

She has no leads on the eight missing bodies other than they were all under 30 when they died and all buried in the same section of the graveyard.

Ace is now working as a morgue assistant. George is writing law papers for Judge Abbott. Bess is the new Director and Curator of the Historical Society. She's hosting the annual Lovers' Vigil being held there, and Nancy Drew Investigations is sponsoring the event. The Vigil is about reuniting the souls of long-lost lovers.

Tristan, a young, handsome lobsterman, drops off lobster at The Claw.

Bess makes sure Ace and Nancy meet at The Claw, despite Nancy trying to give Ace some space. Ace says he's been angry that he lost a friend over what wasn't even a kiss. Nancy wants to be friends again. So does Ace, but then the police arrive and arrest Ace for stealing the eight bodies from the cemetery.

There's a new Police Chief, Chief Lovett, and she's reviewing the Community Liaison program. But on the upside, she's a fan of Nancy's.

Ace's parents are hiking the Appalachian Trail, and there's no cell service, so they can't be reached. Ace has been watching his parents' house while they are away, and an arm from one of the missing corpses was found in the backyard by a neighbor's dog. As Nick and Nancy investigate the backyard, they hear more dogs barking around the same time, 10 pm. There have been complaints every night at 10 pm about barking dogs since the bodies went missing.

Nancy and Nick find one of the bodies. It comes out of the ground and walks away. It's missing the arm the dog found. Nancy thinks the missing bodies bury themselves in the morning and then reanimate at night, but she doesn't know why. She puts all of her paying jobs on hold to find out so she can exonerate Ace.

George learns the body with the missing arm was India Burnett. She was the most recently deceased, dying in 1998. The cause of death was inconclusive. She may have been mentally ill, and they found her body on an old yacht called the Lost Time. No one has been on it since India dies.

Nancy sneaks onto the yacht and finds an old journal with scribbles and ripped pages she assumes was India's. In order to avoid a security guard upon leaving, she asks Tristan, the lobster fisherman, to help her hide, which he does. It's clear he's attracted to Nancy.

Later, Ryan realizes that Nancy is looking at a map of the old Horseshoe Bay before they incorporated the eastern marsh in 1999. It's where Nancy and Nick found India's body. If dogs all bark when the bodies emerge, maybe they can use that to find them.

The town council is about to review the quarterly funding for the historical society, which has Bess nervous. Ryan asks her to sit down with the Glasses, the relic-hunting couple who now hold his Porsche hostage after the magical hatchet was destroyed. They want to sell some of the historical society's possession on the black market and share the profits. Bess immediately tells them no. But they hear Bess making an appointment to pick up a new shipment.

The Glasses give Ryan his car back since his part of the deal was to get them a meeting with Bess and nothing more.

Ryan gives Bess a ride to her appointment, but his car's brakes go out, and they hit a tree. He finds a talisman embedded in the engine. Bess discovers that the Glasses pretended to be her assistants to steal her shipment. She wants to confront them, but Ryan tells her to let him handle it because the Glasses are dangerous.

At the Lovers' Vigil, Addy arrives, and she and Bess dance. Nancy hears that Ace was released but assumes he'll want to go home and not to a party after getting out of jail.

George asks Nick why he sold her engagement ring. He needed the money to seal up the veil to protect the kids at the youth center. He didn't mean to hurt her. She knows, but it feels so final. But they both realize they can't live their lives waiting for something that may or may not happen between them. George tells Nick he should download an app and say yes to all of the women who are going to message him.

When Chief Lovette arrives, Nancy explains the Lovers' Vigil. Local legend says that on this night every year, lovers' souls separated in death can find each other. So people write the name of their beloved, seal it in a bottle, and send it out to sea so their souls can reunite if they so desire on this side or the other.

Nancy writes a name and puts it in a bottle. That's when she runs into Ace. They almost kiss when the bottle in her hand breaks, and she cuts her hand. Nancy hurriedly goes to clean it up but leaves the bottle behind.

George does horribly on a paper for Judge Abbott and considers dropping out of school, believing she can't cut it. Carson explains how he tanked his first law school final. He was working two jobs and had to learn how to manage his time. He says the judge wouldn't spend that much time marking up her assignment if he didn't believe she could do better. Carson offers help.

Nancy finds old maps of Horseshoe Bay corresponding to when one of the missing bodies was alive. The bodies are walking the town limits as they knew them during their lifetime. And they meet at Geiger Clearing. It's the site where the town was founded.

When they arrive at Geiger Clearing, the bodies soon show up, and so does Chief Lovette's response to Nancy's text.

They watch in horror as the bodies throw up some sort of liquid and then collapse to the ground.

The next day at the Historical Society, they clean up after the Vigil. Nancy learns that the Glasses stole from Bess and destroyed Ryan's Porsche with a talisman. Ryan makes Nancy promise to stay away.

Of course, Nancy goes directly to the Glass' house and finds Tristan, who happens to be Jonas and Shelby Glass' son. Nancy leaves without confronting them.

The liquid that came out of the reanimated corpses runs into the Horseshoe Bay municipal reservoir, which supplies the town's drinking water.

Back at the Historical Society, Ace finds the broken bottle with his name written inside. He heads to Icarus Hall and confronts Nancy.

Nancy's electricity goes out because she hasn't paid the bill. Ace arrives and shows her the paper with his name on it. She can't deny it because he knows her handwriting. When he leans in to kiss her, her flashlight lens breaks, just like his barometer and the bottle. She tells him they can't be together because they are cursed.