The Director is a super intelligent, highly advanced quantum AI program that was initially created to help and oversee mankind. It controls not only the time travel program, but the government itself. Use of the program to allocate resources and protect the shelters has been what has kept humanity alive.
As it evolved, and time travel was discovered, the director was the one who came up with the Grand Plan and the use of time travel to fix or prevent some of Mankind's greatest tragedies and disasters that it believed were the cause of mankind's fall. The director dictates and assigns all of the missions of Travelers in the 21st century. No missions or actions taken by any traveler team should be done without the Director's discretion. The director has also calculated all T.E.L.L.s which make the consciousness transfers possible.
In the future, members of an anti-Director faction object to an AI making decisions they'd rather make themselves and it is their own personal mission to destroy it.
The Grand Plan
The Director, a Quantum AI super computer, has calculated all events from Earth's history and has devised a series of actions, or missions both large and small that it believes will stop the destruction of the earth and the near extinction of humankind.
Some of these actions are quite large, such as diverting a huge asteroid that will strike earth and cause a chain reaction leading to an ice age, or stopping the creation of a bio-engineered super crop that will devastate the entire globe and make all surface land unfarmable. Some events are not as large, such as protecting a future president, etc, but every mission has been calculated as vital to saving the future of the human race.
Some missions require an entire team, and some only one or two members, and there is the rare mission that requires teams to work together. On some combo missions, each team's ultimate mission goal may not the same, but they have to work in concert for the overall success of both of their goals.
No mission is unimportant, as each is a key element in the Grand Plan that affects the ultimate outcome; Saving humankind.
Acting outside the Grand Plan, betraying your mission, or exposing yourself or fellow travelers can all be considered acts of treason, which will usually result in a trial of fellow travelers and the director. If found guilty, the penalty is death by overwrite, meaning another traveler's consciousness will overwrite the old, in essence killing the previous traveler, but not the host.