The purpose of this study is to discern the didactic potential of fanfiction and transmedial storyworlds in a classroom context. This is studied through the analysis of works from two transmedial storyworlds: Star Trek and Sherlock Holmes. The works are examined using Herman’s (2009) four narrative elements. The study shows that fanfiction writers change one or more narrative elements of a story to build their own narrative. Some writers keep the narrative elements intact but instead write stories that reflect their own lives. Both the Star Trek and Sherlock Holmes narratives are prototypical stories that are easy to follow and recreate and that might be why they are popular in a fanfiction context. The study shows that fanfiction has a didactic potential and that one important aspect of using fanfiction in the classroom is to be open to student’s interpretations of the narrative.