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.

George and Harold are forced to contemplate a world without Captain Underpants.

Time has gone wrong, and best friends Dak Smyth and Sera Froste, together with the young Hystorian Riq, must use the infinity ring to travel back to one of the Great Breaks--a mutiny on the Santa María--to correct history and defeat the SQ.

The dark wizard Maldred has trapped dragon master Eko as well as wizards who have opposed him, all of them frozen in time and space inside a wall in his hideout; so Drake and Worm set out to seek the help of the Time Dragon--but when a imp named Beezel interferes Drake ends up back in his own past, and he must find a way to get back to the present.

Mira receives a postcard from her missing mother from Paris and she and her father travel to France to search for her, but while visiting Notre Dame, Mira touches a gargoyle and is whirled into the past, where she meets the famous painter Degas and catches a brief, shocking glimpse of her mother.

Children's birthdays are always strange in Willow Falls, but when Connor's little sister Grace falls into a frozen state on her tenth birthday, Amanda and Leo must travel back in time to find out what force prevented Angelina from casting the blessing that would have protected her.

When the three members of the Bad Guy Brotherhood buy a time machine to keep the younger Melvin from gaining his superhero powers, Melvin and his sidekick Candace, disguised as pirates, travel back in time to stop them.

While a boy tries to face his bedtime fears, his stuffed rabbit, Floppy, tells a secret about his bed, which soon takes them to a play date with a dinosaur.

"In Poison at the Pump, Patrick and Beth travel back in time in the Imagination Station to London, England, during the cholera epidemic of 1854. The cousins join Dr. John Snow, Florence Nightingale, and Curate Henry Whitehead in a thrilling scientific adventure to discover why this disease was killing people around Broad Street. In their quest for truth, Patrick finds himself a prisoner in a workhouse. Will he escape? Can the cousins help Curate Whitehead...

In Paris with his parents to sell family heirlooms, fourteen-year-old Greg Rich suddenly finds himself four hundred years in the past, and is aided by boys who will one day be known as "The Three Musketeers."