The Mystery on the Mississippi Trixie Belden (Trixie Belden, Girl Detective Book 15) by Kathryn Kenny

A young detective's riverboat vacation turns into a high-stakes mystery when she discovers discarded graph papers that someone desperately wants back. Trixie finds herself shadowed along the Mississippi River, transforming her dream trip into a suspenseful adventure where seemingly childish drawings hold dangerous secrets. This middle-grade mystery cleverly blends travelogue excitement with puzzle-solving, as our heroine must decipher why these papers matter before they're stolen for good. The river setting provides a constantly changing backdrop that keeps the tension flowing as steadily as the current.

What distinguishes this friendship-centered mystery is how it validates a child's intuition—Trixie trusts her instincts about the papers' importance when adults might dismiss them as trash. The mathematical element of graph paper clues adds an educational layer that will engage readers who enjoy cracking codes and solving puzzles. Young detectives ages 8-12 will appreciate how the ordinary becomes extraordinary, proving that adventure can surface anywhere, even in hotel room garbage. The result is a compelling page-turner that demonstrates how observation and deductive reasoning can unravel even the most mysterious circumstances.