Undisclosed Trilogy Books in Order

At the center of the Undisclosed Trilogy is Travis Marshall, a teenager in Los Alamos, New Mexico, whose life is already cracked open before the bigger mystery even starts. In Undisclosed, a new tragedy and his father's sudden disappearance pull him into secrets that stretch far beyond one family. The story begins like a YA thriller, but it quickly opens into something stranger and bigger.

Los Alamos is the right kind of place for that.

Mills uses the town's long history of secrecy to set the tone. Travis lives in a place where disappearances, rumors, laboratories, and half-explained events already feel possible. Once he starts digging into what happened to his father, he is pulled toward hidden groups, buried agendas, and a war between Guardians and Watchers, both of whom claim to understand more about human origins than the rest of the world. That mix gives the trilogy its identity. It is part conspiracy story, part science fiction adventure, and part coming-of-age tale.

Travis is what keeps it human. He starts the series as a boy living in the shadow of family loss, angry at the world and not especially equipped for what comes next. Then the ground shifts under him. His search becomes a fight for answers, for survival, and eventually for people he cannot bear to lose. Jayde and the other outsiders around him bring team energy to the books, but they also complicate the question of trust. In this world, knowing who is on your side is half the battle.

The trilogy also grows as it goes. Retribution / Decoded takes Travis beyond the first book's immediate shock and into a wider hunt involving altered DNA, his missing brother, old mysteries, and a legendary artifact. Clandestine / One pushes even further, bringing in a shadowy agency called ONE, an airborne threat, and the feeling that local secrets have become a danger to far more than one town. The stakes keep rising, but the through-line stays clear. Travis is trying to understand what was done to his family and what role he is meant to play in a much older conflict.

This is not quiet science fiction.

The books like motion. They move through labs, safe houses, cross-country searches, hidden enemies, and sudden bursts of danger. Even when the mythology gets bigger, Mills keeps the focus on pursuit, betrayal, and urgency rather than long lectures about the universe. That makes the trilogy an easy fit for readers who want speculative ideas delivered with thriller pacing.

If you are deciding whether this series is for you, think YA conspiracy thriller first. The appeal is not just the question of what is true about humanity's past. It is also the pressure Travis feels as he grows from confused teenager into someone forced to act before he understands every part of the board. Read it in order. This is one long story, and the reveals land better when you follow Travis from the first disappearance onward.