This book is mainly based on the life of a Rifter named Lex in the group The Hollows. The Hollows train young travelers, called Rifters, to go through time without even caring about consequences. The only other time travel group, The Tesla Institute, is against this way of traveling through time without care and do anything to stop The Hollows. When Lex’s girlfriend dies on an assignment, he will do anything to get her back, even if it includes breaking into The Tesla Institute to get a special piece of tech that makes sure he doesn’t collapse time.

Lex and Amber are two Rifters (time travelers) with no knowledge of each other or what their lives were like before they were pulled into the time-traveling world.  Lex is part of the Hollows, a band of scruffy Rifters whose mission is to stop the Tesla institute at all cost.  Amber is a student at the Tesla Institute, run by the famous (or infamous?) Tesla.  Their goal is to preserve the time stream, or so Tesla claims.  But as Amber and Lex embark on journeys that lead them to each other, they will learn things that will change their

Extracted is a book about two fictional groups who can time travel.  One is the Tesla Institute, and the other is the "Hollows".  The Hollows fight to disrupt time and the Tesla Institute protects it.  There are two main characters, one with the Tesla Institute (Ember) and one with the Hollows (Lex).  On one of Lex's missions, he and his girlfriend are sent to retrieve an artifact from the Amber Room. But on that mission, they run into a problem and his girlfriend dies.