Now You See Him, Now You Don’t

Dexter discovers that his experimental formula renders objects temporarily invisible. The key detail is that the invisibility can be rinsed off with water, making it reversible. When lightning damages his equipment, part of his glasses become invisible, confirming the formula works but only temporarily.

Earlier, the thunderstorm that damages Dexter's equipment is what actually causes the formula to become active.

Arno discovers a little-known 1912 statute that makes gambling legal on college land. Using this loophole, he plans to transform Medfield College into a gambling destination, essentially exploiting a legal technicality to run his criminal operations under the guise of legitimacy.

Dexter and Schuyler find this statute when they sneak into Arno's office using the invisibility formula.

Dexter hides himself using the invisibility formula and stands directly behind Higgins as he takes his golf shots. While invisible, Dexter subtly guides Higgins' club and swing, producing a string of impossible hole-in-ones that impress sponsor Timothy Forsythe enough to let Medfield re-enter the science contest.

This plan comes after Medfield is dropped from the Forsythe contest and Higgins needs to convince Forsythe to let them back in.

Cookie, Arno's chauffeur, disguises himself as a janitor and spies on Dexter and Schuyler while they test the invisibility formula. He waits for an opportunity and steals the crucial sample, which Arno later uses for the bank robbery.

Earlier, Arno becomes suspicious when he sees Dexter blinking back into visibility in the shower, prompting him to order closer surveillance.

When Cookie steals the formula, he swaps it with a different spray bottle. During the demonstration, Dexter unknowingly uses this swapped (wrong) spray, which contains no invisibility formula. The demo collapses in embarrassment, costing Medfield the chance at the prize money.

Dexter doesn't realize the formula has been stolen until after the failed demonstration.

Dexter and his friends pursue Arno and Cookie in their invisible car during the bank heist. They manage to force Arno's car into a swimming pool, which washes off the invisibility formula. This makes the car, Arno, Cookie, and the stolen money all visible again, leading to their immediate arrest.

Dexter had planted a walkie-talkie in Arno's office, allowing Schuyler to overhear the bank robbery plans.

During the second demonstration at the award ceremony, Dexter's spray unexpectedly makes Dean Higgins' upper body turn invisible in front of the astonished crowd. This shocking, real-life display of invisibility convinces the judges that the invention is genuine and remarkable, securing the $50,000 prize for Medfield.

Higgins had been reluctant to use the invisibility formula, preferring the safer bee study.

Using the invisibility formula to become invisible, Dexter and Schuyler sneak into Arno's office to investigate his suspicious activities. There they discover documents proving the 1912 statute that allows gambling on college land and learn about Arno's plan to turn Medfield into a gambling town.

This happens shortly after Arno arrives as the new mortgage owner, reminding everyone of his past crimes.

Arno plans to use the invisibility formula to commit a bank robbery. After stealing the formula from Dexter, he and Cookie attempt to rob a bank while invisible, believing no one will be able to see or stop them.

Schuyler overhears the bank heist plans through the planted walkie-talkie.

Dean Higgins reveals during a board meeting that Medfield College faces severe budget shortfalls and could lose funding. The college desperately needs money to stay afloat, which is why winning the Forsythe science contest prize of $50,000 becomes so important.

This financial crisis sets the stakes for the entire movie and motivates the characters to enter the science contest.

A thunderstorm strikes Medfield College, and lightning damages a good portion of Dexter's delicate laboratory equipment. The very next day, Dexter discovers that part of his glasses have become invisible - the lightning strike actually activated his formula, creating the first successful invisibility effect.

The storm and lightning damage happen during the scene where Professor Lufkin shows Dexter's experiment to Dean Higgins.

Arno notices Dexter suddenly blinking back into visibility in the college showers - meaning the invisibility formula is washing off. This unexpected sight makes Arno suspicious that Dexter has invented something real, and he begins watching the student more closely.

This moment directly leads to Arno ordering Cookie to spy on and steal the formula.