At the same time that creativity, play, and inquiry are receiving special focus in academic, professional, and educational settings, mandated assessments have never been more prominent, despite public debates that question the value of such testing. In the context of these apparently contradictory developments in literacy education, as a "telling case," we explore writing as a strand within the multimodal compositional processes of one boy in one classroom during a three-day mandated writing assessment that was also a performance-based and process-oriented assessment. There are two primary areas of interest here: (1) what is made visible when one examines processes more closely, in an ethnographic and observational fashion, and (2) what a multimodal understanding of compositional processes offers, especially in terms of the learning that happens across modes of expression.