Social studies instructional experts have called for a move from a knowledge-based curriculum to conceptually-driven inquiry, though tools for educators in meeting this challenge are lacking. Simulations are potentially a powerful inquiry tool to transform students' ways of seeing the world through realistic interactions with complex social studies concepts. However, there is a paucity of research in the game-based learning field on how to design and implement games in classroom contexts. This design-based investigation explored the fifth-grade social studies simulation "Smalltown." In "Smalltown," students interacted in an imaginary town to explore economic and civic concepts through shopping, working, voting, and legislative activities. The goals of this investigation included studying this tool and its use as an inquiry-based social studies instructional unit and developing understandings of how simulations are designed and implemented in classroom contexts. This study explored the epistemic frame changes of students participating in the simulation "Smalltown" in two fifth grade social studies classrooms and the design and implementation features that supported those changes.Findings suggest that the simulation transformed students' civic and economic epistemic frames due to three important features: (a) "frame-linked design" were game activities were tied to authentic real-world practices; (b) "framing support strategies" that facilitated students shifting into, and building, a virtual epistemic frame then bridging those understandings to their real world; (c) "social simulation," as opposed to a digital simulation, that allowed for more interaction with peers and an instructional ability to revise the experience as needed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]