After her mother's death, 16-year-old sleuth Nancy Drew (Sophia Lillis) and her father Carson (Sam Trammell) relocate from Chicago to rural River Heights. While Nancy struggles to fit in, Carson is active in local politics, fighting the development of a train line through the town. A local thug named Willie Wharton (Jesse C. Boyd) threatens Nancy one night to try to scare her father into backing down. Nancy was not happy to leave Chicago, but aunt Hannah Gruen (Andrea Anders) helps Nancy realize that Carson moved to River Heights after the death of his wife. Her memories were depressing Carson in Chicago, something that Nancy had not considered. Hannah is advocating in favor of the train line against Carson but is good personal friends with Carson and Nancy.A school bully had uploaded a morphed video of Nancy's friend Bess (Mackenzie Graham), in which she appears to be farting. Bess is mortified at the video and refuses to come out of her room. Nancy identifies the bully as Derek Barnes (Evan Castelloe) from a reflection in the video. Derek belongs to the richest family in town and cares about his social media presence. Nancy works with Bess and her friend George Fayne (Zoe Renee) to follow Derek and take videos that show for the creep he is, always ogling at girls. Nancy then sabotages Derek's shower at the gym and dyes him a Smurf blue color. Derek becomes the laughingstock of the town. Mr. Barnes (Josh Daugherty) threatens to sue Nancy. Carson proves that Derek is also liable to jail time for cyber bullying and gets Barnes to back off. But Nancy has to do community service to avoid jail time for her offenses.While performing community service (8 hours per day for 2 months, at an old age home) as punishment for a prank on a school bully, Nancy meets Flora (Jesse C. Boyd), an elderly woman needing help with an apparent haunting in her home. Excited by the mystery, Nancy stays overnight at Flora's home, along with Flora's niece Helen (Laura Slade Wiggins). Helen hates Nancy for her antics with Derek but decides to collaborate with her for the sake of her aunt Flora. That night, strange things begin to happen, with lights going out and then exploding, cabinet doors and drawers opening, and a cloaked figure appearing and warning Nancy to give up her mystery. Derek and his family are out of town, and hence are ruled out as suspects. But Nancy saw a black Mercedes drive away from Flora's home and Nancy believes that it had the same license plates as Mr. Barnes.The next day, Nancy believes that someone broke in and tried scaring them out. Nancy and Helen investigate, and they find a secret passage that leads outside, revealing how the "ghost" entered the house. The secret passage also contains props the intruder used to simulate a haunting, such as a rigged fuse box to manipulate the lights in the house. The rest of the strange phenomenon is explained by a rig that emits concentrated nutmeg through the house's air conditioning, which triggers hallucinations. George hates Helen as she is Derek's girlfriend. Nancy tries to defend Helen, but George says that once the mystery is over Helen will go right back to making fun of Nancy and her friends to their faces. Nancy figures that someone must have bought a huge quantity of nutmeg to make the concentrated gas.Later, Nancy realizes her father, who is staying out of town on a business trip, has not checked in with her or her aunt Hannah (Andrea Anders) recently. She calls her father's friend Nate (Jon Briddell), who tells her that Carson's meeting is at a campsite and reception must be spotty. Nancy is not convinced, as Carson had told her he would be staying at a hotel.Helen returns to Nancy and says that Derek broke up with her and blamed it all on her. But she also confirms Derek's alibi and rules him out as a suspect. Helen decides to help Nancy to find Carson.Worried that something has happened to him, Nancy and Helen head to Carson's hotel. They discover that he never checked out, and his cell phone is still in his room. Security footage from the previous night reveals Carson was ambushed and kidnapped by Wharton. Nancy's friends Bess (Mackenzie Graham) and George (Zoe Renee) find out that Wharton is also the man who bought the nutmeg used at Flora's house, and Nancy realizes Carson is being kept in the secret passage there.She and Helen head to Flora's house, where they discover Wharton and Nate holding Carson and Flora hostage. Wharton and Nate were working together to sabotage the anti-train movement, and their scheme was meant to force Flora to sell her house so the line could be built through her property. Nancy and Helen work together to save Carson and Flora from their captors, who are then arrested by the police. The next day at school, Nancy, George, and Bess welcome Helen into their circle of friends, and together they plan their next adventure at the Lilac Inn.