The fifteen-year-old Murry twins, Sandy and Dennys, are accidentally sent back to a strange Biblical time period, in which mythical beasts roam the desert and a man named Noah is building a boat in preparation for a great flood. When twins Sandy and Dennys Murry accidentally interrupt one of their father's experiments, they are hurtled out of their ordinary world, across time and space into a mysterious desert land populated by unicorns, seraphim,...

In the Welsh hills Will Stanton, youngest of the immortal Old Ones, joins forces with Merriman, Bran, and the mortal Drew children in a quest through space and time against the powers of evil known as the Dark.

When he goes to spend the summer with his great-aunt in the family's old house, eleven-year-old Drew is drawn eighty years into the past to trade places with his great-great-uncle who is dying of diptheria.

The youngest of the Murry children must travel through time and space in a battle against an evil dictator who would destroy the entire universe.

In fifteenth century Rome, Toby O'Dare, a recently retired government assassin, receives a visit from the angel Malchiah. The heavenly figure instructs O'Dare to solve a grisly murder. But during the investigation, O'Dare discovers that the city is being haunted by an ancient demon and that solving the murder may have disastrous consequences for all of Rome.

Candy Quackenbush of Chickentown, Minnesota, one day finds herself on the edge of a foreign world that is populated by strange creatures, and her life is forever changed.

John has fallen through a forgotten door to the strange planet Earth and is in great danger. Soon the family who befriends him is in great danger too.

For eons, Earth has been under observation by the Firstborn, beings almost as old as the universe itself. The Firstborn are unknown to humankind—until they act. In an instant, Earth's timeline is carved up and reassembled into a patchwork of different eras, from prehistory to the year 2037, each with its own indigenous inhabitants.

Scattered across the planet are floating silver orbs impervious to all weapons and impossible to communicate

...

Lukas, the most accomplished idler in the town of Zara-Petra, steps forward when a traveling conjurer asks for a volunteer and finds himself instantly transported to a strange land.

Sixteen-year-old Alaric discovers how to travel to an alternate reality, where his mother is alive and his place in the family is held by a girl named Naia.