When Jonah and Katherine travel to early 1900s Switzerland and Serbia to return Albert Einstein's daughter, Lieserl, to history, her mother Mileva grasps entirely too much about time travel and has no intention of letting her daughter go.

Jonah, Katherine, Chip, and Alex suddenly find themselves in 1483 at the Tower of London, where they discover that Chip and Alex are Prince Edward V and Richard of Shrewsbury, imprisoned by their uncle, King Richard III, but trying to repair history without knowing what is supposed to happen proves challenging. Author's note includes historical facts about the princes and king.

Time travelers Jonah and Katherine arrive in 1611 to rescue missing child John Hudson, son of the explorer Henry Hudson, but just as the mutiny on the Discovery is supposed to start, Jonah and Katherine's knowledge of history is tested once again, and they fear that more is at stake than just one boy's life. Author's note includes facts about Henry Hudson's explorations.

"What makes you 'you'? Chess has always been the protector of his younger siblings, Emma loves math, and Finn acts silly so he will be adored. They've been a happy family, the three of them and their mom. But everything changes when reports of three kidnapped children--who share the same first and middle names and exact birth dates--reach the Greystone family. This bizarre coincidence makes them wonder: Who exactly are these strangers? Before Chess,...

Twelve-year-old Zola, who has a surprising connection to Jessie, discovers that she's stuck in a fake utopian future, and that those around her are counting on her to help them escape.

Jonah, thirteen, and Katherine, eleven, travel through time to 1918 Russia just as Alexei, Anastasia, and the rest of Tsar Nicholas II's family is about to be executed. Author's note includes facts about the Romanov's and the mystery surrounding their deaths.

Told from separate viewpoints, as evil forces from the parallel world invade their home, the Greystones, their doubles, and friends must return to the alternate dimension to save both worlds.

Amy and Dan Cahill face their greatest challenge on their quest to find the thirty-nine clues, but in order to discover the secrets of their lineage they will have to make a choice that could impact the world's future.

Luke Garner is a third-born in a restricitve society that allows only two children per family. Risking his life, he came out of hiding to fight against the Population Police Laws. Luke inadvertently sets off a rebellion that results in the overthrow of the government. The people are finally free. But who is in charge now? And will this new freedom be everything they had hoped for? When thirteen-year-old Luke Garner unwittingly sets off a rebellion...

Jonah was able to save all of time from collapsing but in doing so gained a twin brother, Jordan, who must learn what has happened and do his own part to save time--and his parents.