As reading continues to become governed by a spatial "logic of the image" rather than strictly a temporal or linear logic of written language (Kress, 2003), and readers increasingly engage with a range of Internet-based texts, a host of challenges ensue for educators and students alike. One of the most vexing of these challenges deals with discernments of credibility. Determining the credibility of multimodal texts, especially on/within the Internet with its "vast network of relations of credibility" (Burbules & Callister, 2000), is particularly challenging because these texts mix images, music, graphic arts, video, and print to make sophisticated claims supported by various forms or types of evidence. This article examines how a group of ninth-grade students grappled with issues of credibility after viewing the controversial Internet video, "Loose Change", a well-documented and comprehensive multimedia account that argues the "real story" of September 11 was covered up by the U.S. government. Findings from the study highlight the range of knowledge and literacy practices students mobilized to "read" the video and the challenges they experienced reading and evaluating the video as a multimodal text. Implications of this work point to the need to consider epistemological issues and further develop tools that can support teachers and students in critically assessing multimodal texts.