Season Four begins as Nancy launches a new investigation to find a group of missing bodies from Horseshoe Bay's cemetery that have been dug up and stolen - or have possibly risen. As Nancy is drawn into this ghostly case, a string of unexplained paranormal crimes leads the Drew Crew to believe that the literal sins of the town's past have returned to haunt the living. Meanwhile, Nancy struggles with yearning for Ace, the man she loves. But when a slow-burning attraction begins between Nancy and the son of Ryan Hudson's newest enemy, Nancy must decide whether this love interest is worth the ire of both her father and Ace - whose own heart may be tempted by a new relationship too.

Ace senses that Nancy is holding back and presses her to give him more information about the curse. Meanwhile, Bess is determined to prepare the perfect meal for Addy's parents, and Nick schedules a brunch date with someone new. Lastly, George's plan to let Judge Abbott know how grateful she is for the opportunity to be his clerk takes a shocking turn.

Nancy and Ace share a sweet moment while working together to find a way to break the curse. Meanwhile, Carson and Jean continue growing closer, but a recent conversation leaves him with an unsettled feeling. Lastly, Jesse and Birdie devise a plan to teach the school bully a lesson.

Nancy runs into an old friend who is in town directing a remake of a horror film called "Longhook", where strange things are happening on set. She's hoping that solving a new case will help get her out of her funk, and a worried Ryan offers to help Nancy since he is a self-proclaimed expert on the original version of the film. Meanwhile, Ace helps Bess rehearse for her role as Victim #1 in the movie. Lastly, George and Nick discover that they were both stood up for meetings by councilwoman, Brie, which gives them both an uneasy feeling.

The Drew Crew discover a clue in an unexpected place and call in someone from George's past to help find answers.

Nancy and the Drew Crew work together to identify a creature. Meanwhile, Bess reaches out to Carson after receiving a cease-and-desist letter. Lastly, Tristan ends up stealing Nancy's thunder during Career Day at the high school.

Nancy and Ace each show up at Nick's loft interrupting his brunch date with Jade. Their behavior leads Jade to wonder if Nick might be up to something shady. Meanwhile, Carson and George help Bess prep for her statement.

Nancy sends a group text to the Drew Crew asking them to meet her at The Claw ASAP. Meanwhile, Ace's dad tries to get him to open up about Nancy. Lastly, Carson makes plans with Nancy to mark the one-year anniversary of losing her mom.

Nancy and the Drew Crew prepare to battle a Sin Eater.

Carson and Ryan work together to help Nancy.

Ryan shows up just in the nick of time to help Nancy. Meanwhile, Nick is thrown by a statement George makes. Lastly, Bess is left feeling concerned after speaking with Ace.

Nancy and the Drew Crew head out to the graveyard after she receives a mysterious call.

Nancy and the Drew Crew's mission to save Horseshoe Bay from sins of its past comes to an epic conclusion as they must contend with Nancy's most shocking discovery yet, one that will determine the fate of her star-crossed love with Ace.