Educators often inquire about the readability of books and other documents used in the classroom, with the idea that readability supports students' reading comprehension and growth. Documents used in classrooms tend to be language-based, so readability metrics have long focused on the complexity of language. However, such metrics are unsuitable for multimodal documents because these types of documents also use non-language modes of communication. This is problematic because multimodal reading is increasingly recognized as a 21st-century skill. One information theoretic solution is transinformation analysis, an approach that measures readability as the difference between the objective entropy of a document and the subjective entropy of its reader. Higher transinformation indicates more information complexity. This study explored the viability of transinformation analysis as a measure of multimodal readability. Think aloud screen recordings from 15 eighth grade "advanced readers" of Episode 2 of the born-digital novel, Inanimate Alice served as the dataset. Findings showed that 14 of the readers attended to less than half the information in the story. Mean readability was .57, indicating a complex reading experience. Readers attended to and recalled information primarily from the linguistic mode, which may have been a strategy for reducing cognitive load, or it may have reflected beliefs that reading is a language-based activity. The strong traditional readers in this study appeared to be weak at multimodal reading. In addition to its theoretical and methodological implications, the study's findings have implications for the practical need to create more opportunities for multimodal reading experiences in contemporary classrooms and libraries.