The Davis Detective Mysteries Books in Order

The Davis Detective Mysteries are Rick Acker's books for younger readers, built around a simple and appealing idea: siblings Arthur and Kirstin Davis run their own detective agency. They have already made a name for themselves solving smaller problems, including locker thefts, but the cases soon get much bigger.

Arthur and Kirstin are partners, so the series works best when their different reactions and skills come into play. They are not adult professionals with police resources. They are young sleuths who have to pay attention, stick together, and keep going when a clue points somewhere unexpected.

The opening book, The Case of the Autumn Rose, takes the Davis Detective Agency beyond its usual school-age work and into an international mystery. That jump in scale gives the story a sense of adventure without losing the kid-detective setup at its center. The fun is in watching Arthur and Kirstin realize that a real case is much messier and more dangerous than catching a locker thief.

Then The Lost Treasure of Fernando Montoya leans even further into adventure. The siblings search through treacherous gold fields, shark-infested waters, and the remains of a buried ship in pursuit of a lost treasure. It is a mystery with a treasure-hunt engine, so the locations and obstacles matter as much as the clues.

These are brisk, clue-led mysteries.

The series does not ask readers to memorize a big fantasy world or follow a long-running adult conspiracy. Instead, it offers two connected adventures with the same sibling team and detective-agency premise. Starting with The Case of the Autumn Rose is the natural choice because it introduces Arthur and Kirstin's partnership before the second book sends them on a wider-ranging search.

For families and younger readers who like mysteries with travel, hidden history, and capable kids at the center, the Davis books are an easy place to start with Acker. They also offer a useful contrast to his later legal thrillers. The shared thread is his interest in puzzles, evidence, and people trying to make sense of a situation that keeps growing more complicated.