While playing in her tree house, Jesse is intrigued by a falling sycamore seed that slowly spins to the ground. But when she sees acorns falling fast directly down to the ground, she must solve the riddle while learning about propellers and windmills and using technology to understand aerodynamics. Ten-year-old Jesse Steam’s curiosity about how the world works leads her to one mystery after another as she pedals around town with Mr. Stubbs, her tabby cat, keeping her company in the bike basket. Using simple scientific tools and their powers of observation, Jesse and her friends analyze, test hypotheses, and conduct experiments. If the kids get stuck, they know they can count on Professor Peach, a retired science educator, to step in with a clear explanation.