The One Ring RPG: The Darkening of Mirkwood - 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 step forward and hold back the gloom. The Darkening of Mirkwood is a complete campaign for The One Ring, set in Mirkwood 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.