Graduation Day begins where the last book in the series stopped, and Cia, the main character, is in her room. Raffe, a friend of Cia's, busts in and tells her that they were seen leaving the college campus, and this could mean big trouble, because that would mean they were associated with the leaders of the campus rebellion. In this world, you must survive through years of testing to get into the Commonwealth school, and Cia and Raffe have only just realized that this life or death system of judgement is brutally wrong.
Cia eventually gets a job working with President Collindar, one of the executives for the Commonwealth education system. Collindar, she finds, is working with the rebels to end the Testing, much to her surprise. However, she wonders if this is simply a cover-up, and Collindar is trying to find out who she herself is really loyal to.
Cia further learns more about this sneaky rebellion. Dr. Barnes, one of the advocated for the Testing, has strategically placed people to lead the rebellion. In fact, the rebellion is basically meant to distract people from the system - Dr. Barnes has the power to bring every one of them down, but the rebellion will keep people thinking that there is something they can do, even if they cannot.
With the right equipment and support, Cia feels that she can end the rebellion and actually stop the Testing once and for all. With the help of President Collindar, Raffe, and many others she meets along the way, she brings down the system. However, this leaves much of society in chaos, which to her was not expected. However, Cia proves that she is an enduring soul, and was able to end something that was obviously wrong.
