Nancy gets a call from the gravedigger at the cemetery. Someone dug a grave, but it wasn’t him. He’s also the mystery caller who warned Nancy about the eight missing bodies. The Drew Crew assumes the grave was dug for Tristan, but he isn’t returning any of Nancy’s calls or texts.

Nick tells Callie he knows she dug a grave for Tristan and asks her not to kill him. She says everyone has to die eventually, but the sin eater is an unbreakable cycle, and it’s her family’s legacy to see that it survives.

Nancy tries to convince Ace to figure out what drove her to the Yacht Club basement to call the sin eater after her phone call with him. They go to the docks in Trenton, beyond where the sin eater can make memories disappear. A dock worker saw a boat catch fire the night Nancy went to the sin eater fountain. There was an explosion, and the boat sank fast. He was surprised when no one reported it, but it was too far away for him to see any details.

Nancy saw a vision of fire when she was prodded with the Ambyth. Could Jane Doe have been on that boat? Ace only remembers himself and his father on the boat his Dad chartered, but no captain. He thinks they should leave this alone, but Nancy insists they solve it. She needs to know what drove her to the sin eater.

Per Ryan’s request, Red, his girlfriend, gets him a hammer strong enough to smash a supernatural object. She also asks him to help her rob the Glasses’ stash of relics now that they are in jail, but Ryan turns her down. They’re in jail; that’s revenge enough for him. Besides, they did what they did to save their son, and Ryan isn’t sure he wouldn’t do the same thing to save his child.

Red doesn’t understand why he doesn’t want to win. He explains that his parents thought like that, and they were miserable their entire lives. Besides, they’d have to go on the run if they robbed the Glasses, and he’s built a family in Horseshoe Bay. He wants to stay. Red agrees to stick around for a while and see how things play out between them.

Bess uncovers that the Masthead Mummy in the basement of the Yacht Club is also known as the Mother of Monsters. Her scream is like an alarm that calls the sin eater.

The Drew Crew decides that if they destroy the Masthead Mummy, then the sin eater can no longer be called. Tristan helps. He uses the hammer to release the mummy, but before he destroys her, she speaks to him. She was sorry there was no justice for what happened to the sin eaters. She was trapped down here for centuries, a prisoner just like the sin eaters the founders forced her to create. Then she said goodbye, and turned back into an essence. Nancy uses that essence to repair the Ambyth so she can see her sin.

Nick tells Callie that her legacy of minding the sin eater is over now that the Masthead Mummy is gone. Callie says he has no idea what he’s done and storms off.

Nick and George get an offer from a millionaire to buy The Claw. He wants to keep it exactly as it is. George is hesitant but realizes she’s ready to move on as long as the deal includes that her sisters can still keep their jobs there.

Nick and Jade plan a vacation. George is accepted to Northern Seattle Legal College for pre-law. Cameron is accepted to the law school at Washington State. They kiss and plan to continue seeing one another when they head off to school.

Nancy and Ace use the Ambyth to see what Nancy asked the sin eater to remove. The ghost was Alice Palermo, the Captain of the boat that Ace and his father chartered. When Ace dropped the curse into the water, it caused an explosion that sent his father overboard and caused Alice to be trapped by a fire inside the boat. Ace had to make a split-second decision about who to save, and he chose his father.

Afterward, Ace called Nancy. He was devastated. She decided to fix it by using the sin eater to erase the event. Ace is furious with Nancy. He called her so she could be there for him. She had no right to erase his memories or to erase Alice’s existence. His horrified by what Nancy has done and storms out.

Ace finds Alice (the ghost) and explains what happened to her. She says she has found her peace and moves on.

Chief Lovette convinced the Rotary Club to cancel the Beltane, the celebration of the Spring equinox, this year. The Chief thinks it’s a danger because it involves a bonfire, remembering regret, and voodoo dolls. But Bess and the Fans decide to host their own Beltane celebration.

Bess confronts the Chief. The Chief’s dream was to be in charge of her hometown police force, but she found it hard to police the people she loved and grew up with. She let things slide, which led to a massive drug problem where people died. She won’t let things slide in Horseshoe Bay. Bess convinces her that the supernatural isn’t the same as drugs. The two come to an understanding.

At the Beltane celebration, there are water spigots that start spewing a black spray. Callie went to the town’s water plant and unleashed 200 years of buried sin into the water supply. Ryan yells for everyone to run, but people are already gasping, screaming, and black veins are showing on their necks.