Adventures in Middle-Earth: Mirkwood Campaign - Rules of Play says:
The Necromancer may have been cast out of Dol Guldur, but a lingering darkness remains over Mirkwood, a shadow that will grow ever longer as the years draw on—unless a fellowship of heroes steps forward to hold back the gloom.
The Mirkwood Campaign offer a complete framework for Adventures in Middle-earth, set in and around Mirkwood, played out over the course of three decades. It allows you to tell your own epic saga, following your heroes in their quest, as the tale of years unfolds before them.