This article presumes that supervision is a category of teaching, and that we all "learn" how to teach better. So it enquires into what novice supervisors need to learn. An anonymised digital questionnaire sought data from supervisors [n226] on their experiences of supervision to find out what was difficult, and supervisor interviews across campus [n7] sought to discover whether there were discipline differences among challenges. Findings suggest that supervision is often troublesome, and that lessons learned during supervision are irreversible, taking the learner to a deeper level of understanding, all aspects of threshold concept crossing. However, there was more that led me from threshold concept to conceptual threshold crossing theory: the darker themes of the data suggest that truly troublesome learning is more like that which occurs in early English literature, where threshold crossing is a common motif. Many early English stories show heroes in liminal, threshold spaces, often the forest, where their skills and methods are inadequate for ordeals. The result is their acquisition of what educational jargon might call leadership attributes and emotional intelligence. The title draws on Tarantino's [1994. "Pulp fiction" [Motion picture]. United States: Miramax Films] "getting medieval" to mean threatening, unpleasant, off the edge of the known. Medieval English stories specialise in challenge: they focus on the "doing," "being" and "feeling" of hard learning. When ongoing challenge from the unexpected troubles supervisors, it also enables, or forces, the acquisition of new attitudes, skills and attributes. I expand conceptual threshold crossing theory by adding the heuristic model of the medieval threshold crossing motif to interpret troublesome learning. Findings raise further research questions: how might novices avoid danger in the dark forest as they traverse their supervisory path and how can institutions support those who find themselves there.