This is an interdisciplinary inquiry-based lesson plan that focuses on critical thinking. Students are introduced to the true story of the first Thanksgiving with the reading of a NCSS Notable Trade Book Thanksgiving: The True Story. Working in cooperative learning groups, students use primary sources to evaluate the accuracy of the Thanksgiving story currently told in many history textbooks. This lesson plan teaches students the importance of using primary sources to construct accurate understandings of historical events. Extensions in this lesson plan also integrate science and technology.