This article shares two National Writing Project Teacher Consultants' interest in examining student engagement in writing flash fiction using mentor texts. Our two-week unit centered on two high school freshmen classes (one class identified as "at-risk" and another class identified as "college prep"), and we found the use of mentor texts assisted both classes in writing in an unknown genre: flash fiction. We begin by describing flash fiction as a genre and the benefits of teaching it in high school writing, share research on mentor texts, and then describe instructional lessons, noting specific texts and procedures employed. We also share samples of students' writing that resulted in a class anthology of their flash fiction pieces. The article ends by sharing differences between classes and implications for writing in high schools.