In 1987, TSR published the module N5: Under Illefarn. It was written by Steve Perrin and illustrated by Jeff Easley and Luise Perenne. It consisted of a 48 page booklet and an outer folder containing maps. The module details the town of Daggerford and offers 4 adventures in the surrounding area including exploration of the titular mines. "Under Illefarn" was the first module produced specifically for the Forgotten Realms campaign setting.
This conversion guide allows DMs to run the original module with 5th Edition rules and provides a reference sheet for encounters. It is intended for 5-6 characters of levels 1-2, or 4 characters of level 3.
To use this conversion guide you will need a copy of "N5 Under Illefarn".