This study proposes a quest-based contextualization (QBC) process, which transforms part of a traditional lecture into a well-defined questing structure. The goal is to create a learning experience by using a systematic game-based questing approach. The QBC procedure is a set of sequential tasks defined by the game designer to reflect the instructional objectives of the course. It is formed as an interaction perspective from which a game system can be materialized, and which aims to improve the quality of the game flow and the user experience in a game-based learning environment. We claim that a game-based contextualization process can be used to restructure a traditional lecture in terms of educational quests. In particular, it was hypothesized that the design of such a quest-line should be constructed as a questing structure based on the chain of events, which are extracted from lecture notes. In the formulation of this design, the key events were discussed in an interview with an expert (i.e. content specialist) from a target field. This interview was transcribed, and further analyzed using an iterative qualitative approach as an interpretive analysis technique where an inductive proposition is considered for contextualization of data. This research used a thematic analysis methodology to explore the situations, which are suitable for questing and might be expandable into categories. Furthermore, questable points from the data were captured and situational elements and conversational key points were rigorously categorized. After building the initial mapping, we conducted a second interview with the same area expert to refine our preliminary findings. To evaluate our approach from the game design perspective, we sought advice from a small group of game design experts and practitioners who are recognized knowledgeable individuals in educational game development. Based on the opinion of four game design experts, the questing structure was revised and several game elements, such as extra battles, puzzles, and achievements, were added to support the elements of fun. Three of the experts argued that the proposed questing structure was highly educational, while the fourth claimed that such an improvement was partially important. These findings, while preliminary, suggested that a well-defined questing structure should be useful to improve the quality of a game-based learning environment.