The ISEE was designed to reinforce the roles of the National Incident Management System (NIMS)/Incident Command System (ICS), which was established in 2004 by the U.S. Department of Homeland Security to be the standard for all emergency response organizations. The ISEE provides a database of local resources (personnel, vehicles, equipment) with realistic response times. It also promotes the use of ICS forms for profiling strategies, such as an incident action plan. Further, the ISEE logs events and communications for after-action review. Among its numerous benefits for those who use it for incident response simulations are its ready accessibility for anyone with an Internet connection; its flexibility for training in simulating various types of emergency scenarios; its defining of the roles and responsibilities for incident command as defined by the NIMS/ICS; and its provision of “situational awareness” in the form of a master scenario event list. The latter contains essential scenario events in text, pictures, sound clips, or videos. This article describes what is involved in preparation for an ISEE exercise, along with the features of the real-life, real-time exercise. This article concludes with a description of a 2007 use of the ISEE by the Northwest Vermont Local Emergency Planning Committee in an incident command simulation in Enosburg, VT. The scenario involved a simulated commercial plane crash on a nearby mountain, which required a response from the United States and Canadian law enforcement, fire, rescue, and medical units. Prototype exercises like the Enosburg plane crash give both technologists and emergency responders a better understanding of what is required to reach the full capabilities of the NIMS vision. 5 notes