In recent decades, a wealth of studies on second language writing and plagiarism have emerged, particularly with the increase of international students enrolling in academic institutions that favor English-medium instruction. In most of these studies, the plagiarism-related variables (e.g., paraphrase) under scrutiny are determined by the researcher prior to the study being conducted; few studies, however, have examined plagiarism-related variables as determined by students. The purpose of this study was to investigate five undergraduate L2 students' experiences and concerns with source-based writing and plagiarism over the course of one semester within the context of the students' in-semester coursework assignments. Results show that mitigating factors, such as the context of assignment guidelines, disoriented students as they worked on their assignments. These factors, in turn, played a critical role in the agential moves students made to complete their assignments and the efforts they put forth to become members of their academic communities. Pedagogical implications for instructors of English as a second language and writing tutors are discussed.