Vaughn has been acting strange since discovering that his mother may still be alive. Josie believes he is thinking about going through the wormhole, so when Lucas's gravity device shows that the wormhole has opened, they rush to the science lab to check it out. By the time they get there, the wormhole is closed. As Josie stands over the spot where the wormhole opens, wondering what to do next, she is suddenly swallowed by the wormhole, and finds herself in 1879. She soon meets 'Headmistress Durst', who believes she is one of the new students, arriving early. Headmistress Durst forces Josie to change into appropriate attire for the school, considering what Josie is wearing quite inappropriate. As she tries to find her way back, she bumps into Blake Holsey- a boy about the same age as herself. After a tour of the school grounds, talking about school construction, Josie finds out that Z's office floor has a subfloor made of by palladium. Josie and Blake walk past Z's office as the wormhole opens and Vaughn, Corrine, Marshall, and Lucas try to get Josie to go back through with them. Blake, however, pulls Josie back and the wormhole closes, trapping them all in the past. Josie explains to Blake who she really is and that they now need his help to return to the future.
However, 'Headmistress Durst' appears and tells them that she received a call from the train station, confirming the arrival of the 5 new students, making the five currently standing before her imposters. Josie asks Blake for help but he refuses. Josie, Vaughn, Lucas, Marshall, and Corrine are locked at Durst's office.
The five of them realize that an approaching storm will have the power to reopen the wormhole and they plan to rush the police officers when the door opens, intending to escape. The door opens and it is Blake in the doorway. He believes Josie and has decided to help them. Josie asks why he believes her and he shows Josie her clothes and her watch.
With Blake's help, the Science Club recreates Franklin's experiment. At the same time, Headmistress Durst, a police officer, and the architect Mr. Avenir try to break down the door. Blake and Vaughn are trying to hold as lightning strikes the kite, running down the kite string into Professor Z's office and opens the wormhole. They tell Vaughn to hurry but Vaughn feels that Blake isn't strong enough to hold the door. As the wormhole begins to close, successfully transporting Josie, Lucas, Corrine, and Marshall to the present, Vaughn leaps into it at the last second but doesn't meet up with the others in the present. Headmistress Durst, the police officer, and Mr. Avenir get inside, only finding Blake. Headmistress Durst and police officer decide to look for them around the school. Mr. Avineer says 'good job Josie'. Turning to Blake, he tells him that they need to discuss Blake's future.
In the present, Corrine, Marshall, Lucas and Josie return realize that Vaughn isn't among them. Vaughn returns to 1977, 10 years before he was born. The Janitor tells him that Vaughn needs to stay hidden for a while because there will be an event occurring that Vaughn cannot interrupt.
Back at present, Corrine says that she has found information about Blake Holsey but not about Vaughn, meaning it is unlikely Vaughn was left in 1879. Josie decides to help Vaughn. She goes into the hall; the Janitor is fixing a lamp when time freezes and Josie2 appears, telling the Janitor that nothing good can result from this. The Janitor doesn't seem to care and Josie2 disappears, time unfreeze, and the Janitor watches Josie leaving.