Chipotle's (CMG -1.59%) stock price has been under pressure lately. Hedge fund manager David Einhorn contends that, not only does Yum! Brands' (YUM 0.55%) new Taco Bell menu pose a threat, but also that the burrito king is overvalued. Indeed, the company has underperformed the likes of Wendy's (WEN -0.28%), McDonald's (MCD -0.61%), and Whole Foods (WFM)while carrying a higher valuation.

Chipotle's growth prospects may be brightening, however. The company's sole ShopHouse location has done well enough that management is opening two more of the Asian restaurants. Rex Moore visited the Washington, D.C. location and talked with the man responsible for the ShopHouse idea. In this installment of our multi-part series, we discover what triggered management to expand. (See all parts of the series linked below the video.)

Part 1: Chipotle's Next Huge Opportunity

Part 2: Chipotle's Small Bet Could Pay Off Big

Part 3: What is Chipotle's ShopHouse, Anyway?

Part 4: Why You'll Find Real Asian Food at Chipotle's ShopHouse

Part 5: Are Customers Buying What Chipotle's ShopHouse Is Selling?

Part 6: Sustaining a Strong Brand is Not Easy