Seventh grader Charlie Winter has never stopped believing he can find his missing mom, even when his dad has given up hope. Three years after she vanished on Charlie's birthday, his mom's disappearance remains a mystery no one wants to talk about. No one, that is, except Charlie's grandmother. Then, during a strange snowstorm, his grandmother is injured and Charlie learns a secret: she's a time traveler. And so is he.

Soon Charlie embarks on a dangerous adventure with his three best friends, searching the past for a magical silver amulet he believes is the key to finding his mom. As they cross continents and centuries, rescuing animal companions along the way, Charlie and his friends discover they aren't alone. Malcolm Mordrex, a vengeful time traveler seeking the same amulet for darker purposes, is chasing them.

With harrowing obstacles at every turn and his friends thrust into a terrible trap, Charlie must find a way to defeat Malcolm and face a choice about his own past--a choice that could mean life or death. And time is ticking down . . .