Josh is separated from his father and sister when he and his mother, Eve, are pulled down into the primeval world of 10,000 BC. Thrust into the wild alongside prehistoric predators, Josh is forced to grow up quickly, shifting from someone who relies primarily on humor and charm to a protective and capable fighter.

A former pre-med student, she is thrust into 10,000 BC when a massive sinkhole opens in Los Angeles. She serves as a fierce protector of her father, Sam.

Eve Harris. Her primary drive is keeping her family together after being separated by time. Eve is driving her teenagers, Josh and Izzy, when the massive sinkhole opens up. She and Josh plummet into 10,000 BC, while Izzy remains above ground. Before the sinkhole, Eve had separated from her husband, Gavin, due to his erratic behavior and alcohol use. She fell into a relationship with Gavin's best friend, Levi Delgado.

He is a former Air Force pilot who initially struggles with "visions" of the prehistoric past before realizing they are actual childhood memories. When his wife (Eve) and son (Josh) fall into the massive La Brea sinkhole, Gavin experiences flashbacks of 10,000 BC. He eventually finds a way to travel back to 10,000 BC alongside their daughter, Izzy.

He is a United States Air Force pilot, Gavin Harris’s best friend.

Before the sinkhole, Scott was an anthropology graduate student from Australia working as a tour guide at the George C. Page Museum next to the La Brea Tar Pits.

Lucas fell into the sinkhole alongside his mother, Marybeth Hayes, an LAPD narcotics officer.

Dr. Sam Velez, Riley’s father and a core leader among the clearing survivors. As a highly skilled physician and former U.S. Navy SEAL, he serves as the primary medical provider in 10,000 BC. He relies on his tactical background to keep the group safe from primeval threats.

Izzy’s journey evolves from a 16-year-old coping with trauma and the trauma of falling in a sinkhole