In season two, Griffin and Harper unravel new mysteries about The Tremont, and Harper follows the real ghost back to the 1930s to learn more about her family's deep-seated connection to the hotel. When the power source to the time machine is unintentionally taken and the portal disappears, Harper becomes trapped in the past with her great-uncle Sam and great-great-grandfather Elijah, while her great-grandmother Daisy is left to navigate the present. With help from Savannah from her new life in 1962, the friends attempt to fix the time machine and bring back the portal before it's too late and their lives are forever changed.

A new ghost checks into room 205 and starts wreaking havoc around The Tremont. After learning the evil presence will ruin their lives by 2024, the kids race to solve a tangled mystery in the past that may hold the key to defeating the ghost in the present and saving the Dunns and the Campbells from a very bleak future.