Griffin Campbell and his family move to a new town, take ownership of an abandoned hotel and hope to restore it.
Griffin and Harper realize they've time traveled to the time period before Savannah's disappearance; when they go back again, they think they see Savannah getting taken into the woods.
Griffin and Harper learn the camp dance is coming up, and that was the day Savannah went missing; Harper meets Jess and learns her mother did go to camp and hated Savannah.
Harper asks Griffin to meet her at the portal after school, but when Griffin gets home, he discovers his grandfather has arrived for a visit.
Ben is upset by the flurry of news reports marking the thirtieth anniversary of Savannah's disappearance, while Zoey and Wyatt see it as the perfect opportunity to finally capture her ghost on tape.
Griffin and Harper observe as young Ben and Savannah sit around the post-dance campfire when, suddenly, Savannah is spooked by a counselor dressed as the legendary Moss Man.
Griffin and Harper are grounded after they are caught together outside of The Tremont. Soon after, they sneak back through the portal with the hope of still finding Savannah.
Harper and Griffin escape after being detained by the police and find young Jess, who reveals new details about her relationship with Savannah.
Once Griffin and Harper learn they can't reopen the hatch to let Savannah in, they quickly go back through the portal.
Griffin and Harper successfully travel to the past, where they find Savannah working at The Tremont.
Harper travels back in time to the date her father died in hopes of trying to change the outcome.