This study explored online mentoring dialogues of first-year science teachers (FYSTs) to construct a model that was informed by metaphors in teaching dilemmas. Nine teachers' yearlong threaded dialogues were archived and first analyzed by Windschitl's (2002) four dilemma categories, and later by Lakoff and Johnson's (2003) conceptual metaphor theory. Particularly, we charted conceptual metaphor systems and schematic elements of FYSTs' teaching practices in conceptual, pedagogical, cultural, and political dilemma categories using computer-mediated discourse analysis. Findings indicated that the FYSTs' mentoring dialogues were predominantly pedagogical dilemmas (64.34%), mostly related to mastering the art of facilitation. The conceptual metaphors and schematic elements include (a) "Teaching is a trip" within a path schema, (b) "Teaching is a race" within an up-down and more-less visual field schema, (c) "Teaching is policing" within a sanctioned land schema, and (d) "Teaching is building a house" within a construction site schema. This study contributes to the understanding of challenging factors that FYSTs encounter and also illustrates the functionality of the conceptual metaphors for teacher effectiveness.