In a future where the Population Police enforce the law limiting a family to only two children, Luke has lived all his twelve years in isolation and fear on his family's farm, until another "third" convinces him that the government is wrong.

When a diphtheria epidemic hits her 1840 village, thirteen-year-old Jessie discovers it is actually a 1995 tourist site under unseen observation by heartless scientists, and it's up to Jessie to escape the village and save the lives of the dying children.

Thirteen-year-old Nina is imprisoned by the Population Police, who give her the option of helping them identify illegal "third-born" children, or facing death.

In a society that allows families to have only two children, a group of third-borns tries to save themselves and others like them.

The Greystone kids thought they knew. Chess has always been the protector over his younger siblings, Emma loves math, and Finn does what Finn does best--acting silly and being adored. They've been a happy family, just the three of them and their mom.But everything changes when reports of three kidnapped children reach the Greystone kids, and they're shocked by the startling similarities between themselves and these complete strangers. The other kids...

In a future where the law limits a family to only two children, third-born Luke has been in hiding for the entire twelve years of his life, until he enters boarding school under an assumed name and is forced to face his fears.

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.

When thirteen-year-old Luke Garner unwittingly sets off a rebellion which sweeps the country and ousts the Population Police from power, he quickly realizes that the new regime is corrupt and he may hold the only key to true freedom.

Eleven-year-old Marin and her neighbor Charley hope that by preventing a disaster that occurred twenty years ago, they can save Charley's dad from a future of guilt and self-destructive behavior.

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