A young man and woman are chased by a group of hooded men intent on killing them and taking a device that they carry.

The film fastforwards sixteen years later, to the day before Gwendolyn "Gwen" Shepherd's sixteenth birthday.

They hold a special regard for Charlotte as she possesses a secret genetic mutation, inherited by only one female per generation, that gives her the ability to travel back in time.

When Charlotte suddenly becomes ill, Gideon rushes her to a mysterious secret society, the Order of Count Saint Germain; he apparently is a carrier of the same gene.

The Order's guards fear a conspiracy, since decades ago Grace helped the previous time travelers, Lucy and Paul, escape.

Due to the theft of the previous chronograph by Gwen's cousin Lucy, blood samples have to be collected from all of the formerly living carriers to finish a second device.

When Gideon and Gwen visit Lady Tilney in 1912, Lucy and Paul suddenly appear, warning Gwendolyn of the dangers of finishing the Chronograph and of the Count's plans to sacrifice her life to achieve his goals.

Back at headquarters, only Gwendolyn believes in Lucy and Paul's sincerity, while the Guardians are convinced of a plot by the Florentine Alliance that has been fighting the Count of Saint Germain for centuries.

Falk de Villiers, grandmaster of the lodge, wants to control Gwen and is worried about her curiosity, but Gideon starts having some twinges of doubt.

At night, they sneak into the Order's archives to find an ancient prophecy about themselves, but the secret documents were transferred to a bank years ago.

Security guards break in, and in trying to escape, Gwen falls many stories to the ground from the top of the observatory tower.

Falk de Villiers quotes the prophecy of her icy death and tries to prevent any efforts to save her life.

Gwendolyn goes to the big school ball wearing her cousin Lucy's dress and being accompanied by Gideon.