This report presents a modular scenario package, which is one part of the MASK 2.0 tool. The purpose of MASK 2.0 is to provide Swedish regions with a tool to conduct preparedness planning for civilian mass casualty incidents during war. The modular scenario package presented in this report consist of two parts: a national scenario and type events. The scenario package is considered "modular" because the national scenario is the same for all 21 regions, but should be adapted to the local context by combining it with various type events. Additionally, each region should develop at least three scenarios in order to explore various outcomes. Hence, the scenario package is designed to be able to vary the sequence of events. After the regional scenarios have been developed, they are to be entered into the MASK software, which provides the casualty outcomes from the civilian mass casualty incidents. The report begins with a more detailed description of its purpose and intended audience. Thereafter the method used to produce the modular scenario package is described, as well as its scope and assumptions. The subsequent chapter provides instructions for how the user, as part of a working group, can combine the national scenario with type events to develop regional scenarios. Finally, the national scenario and the type events are presented.