12-year-old Griffin Campbell and his family move to the small town of Sulphur Springs and take ownership of an abandoned hotel rumored to be haunted by the ghost of a girl who disappeared decades ago. Griffin befriends Harper, a bright-eyed, mystery-obsessed classmate and together, they uncover a secret portal that allows them to travel back in time. In the past, they’ll attempt to uncover the key to solving this unsolved mystery, a mystery that affects everyone close to them.
Griffin and Harper realize they've time traveled to 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 is the day Savannah went missing! Later, Harper meets Jess, and learns her mom did go to camp and hated Savannah!
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.
A 12-year-old boy and a thrill-seeking classmate discover a secret portal that allows them to travel back in time and uncover clues about a mystery involving a girl who disappeared decades ago from a Louisiana town.
Griffin, Savannah and Harper find themselves face to face with Harper’s carbon copy, Daisy, and the Tremont ghost sends Harper and Griffin an important message.
Griffin frantically searches for the missing crystal and helps a panicking Daisy to navigate her modern surroundings; meanwhile, Harper has a cryptic vision at the springs.
When Daisy struggles at pretending to be Harper, Griffin searches for the crystal to swap them. After the Twins don't hear from Topher, they try to capture the ghost themselves.
Harper returns home and fills Griffin in on the deed, stolen land, and her visions of a fire. After Sam disappears, Savannah finds a note saying that he’s travelled to the future.
The Campbell's and the Dunn's prepare for the Tremont’s Grand Re-opening! Harper and Griffin realize that the crystal is cracking which may prevent the Time Machine from working.