From the introduction: Battle for the Undercity is a D&D 5th Edition adventure designed for a DM’s use in any Forgotten Realms campaign. This adventure includes three, separate three-to-four hour long missions that can be run in any order, depending upon the needs and composition of your party members. While this was designed as a Level 8 adventure module to be run in the recommended time, you will find notes to adjust the missions to increase or decrease their difficulty and length A three-part adventure for 7th- to 9th-level characters