Major Brett Hostam is a member of the Delta Force. His new assignment takes him to a strange, highly selective training course. The academic and physical classes are challenging. On the course, Brett is known only as 2023-5C.

Simone Harris, assigned the designation 2023-4D, is also training. She is seconded from the CIA.

If they succeed, they will join the Temporal Investigations Department (T.I.D.). Several other candidates do not make it.

Selection and capability are the key criteria. Most people cannot time-travel. Consequently, there are very few active agents conducting missions across the ages.

A secret chamber transports them and their new boss, Todd Caraway, 2,000 years into the past. Each stage of the training is a test to see if they have the capability and can survive the experience. Their instructor in a Canadian wilderness cabin is the enigmatic Krista Lysander, whose own past is complicated.

They are learning about TID, its competitors, missions, chambers, and the time line. They also learn how mistakes can lead to death or just embarrassment. Simone and Brett learn how to use wrist devices. These allow some jumps in time and place. The two trainees suffer the consequent side effects of jumping with time lag. They suffer the dangers of using the apparatus while learning its capabilities. The further away you are from their timeline, the worse the effects are.
They finish their training and return to their timeline via the chamber.

They must immediately stop the Russian surveillance of Todd and his family. Operating in the USA, Russia's version of TID is creating dangers that must be overcome.

TID has to deal with current and historic global politics. TID's managing committee and bosses are constantly interfering with historical research. Threats and dangers may appear at any time or place.