The Mystery Soil Lab, a playful, inquiry-based laboratory project, is designed to develop students' skills of inquiry, soil analysis, and synthesis of foundational concepts in soil science and soil ecology. Student groups are given the charge to explore and identify a "Mystery Soil" collected from a unique landscape within a 10-mile radius of our university by determining its soil formation and development history, associated plant community, and official taxonomic designation. Student groups have 4 consecutive weeks to conduct the lab assignment using observation and laboratory techniques. After 4 weeks, students present their findings by describing their process of inquiry, soil analysis results, and the conceptual reasoning behind their hypotheses using key course concepts. This project enhances students' abilities to conduct iterative science using the scientific method, improves foundational knowledge of soil properties and processes, and builds students' skills and confidence for a subsequent, independent soil ecology research project later in the semester.