A group of children and a "spirit" go back through time to discover the beginnings of Halloween.

To prevent the destruction of his planet, teenaged Rigg Sessamekesh, who can manipulate time, must assume more responsibility when he and others travel back 11,000 years to the arrival of human starships.

Alice is sent back to the night of her sister's murder and has until midnight to figure out who the killer is or risk losing her sister forever.

Esmeralda, who's both a princess and a powerful witch, must travel back in time to end a family curse or risk losing her true love, Prince Eadric, forever.

When thirteen-year-olds Jonah and Chip, who are both adopted, learn they were discovered on a plane that appeared out of nowhere, full of babies with no adults on board, they realize that they have uncovered a mystery involving time travel and two opposing forces, each trying to repair the fabric of time.

While on a field trip to New York's Museum of Natural History, Joe, Sam, and Fred travel one hundred years into the future, where they encounter robots, anti-gravity disks, and their own grandchildren.

When he jeopardizes his football scholarship, high school student Kaleo is transported from present-day Salt Lake City to early nineteenth-century Palmyra, New York, where he meets the Prophet Joseph Smith and learns for himself the truthfulness of the Book of Mormon.

Pulled through a glass that brings him back in time, Septimus Heap becomes the apprentice of an alchemist.

In an attempt to find a cure after being diagnosed with Creutzfeldt-Jakob's (aka mad cow) disease, Cameron Smith, a disaffected sixteen-year-old boy, sets off on a road trip with a death-obsessed video gaming dwarf he meets in the hospital.

While working on a time machine for the Spring Science Fair, Ordinary Boy discovers the true identity of long-lost Superopolis hero Meteor Boy.