From the back of the adventure:
"The Grand Conjunction has come to pass!
As a result, the lords of Ravenloft have broken through the Mists and escaped into the Prime Material Plane. Bit by bit, monsters of the demiplane of dread are following behind. And in the midst of all, Azalin the Lich and Strahd von Zarovich play a power game - a game with deadly stakes, most notably the player characters' lives. Unless the adventurers act quickly, death will be the least of their troubles!
This is the second of two adventures that feature Azalin and Strahd von Zarovich in their endless conflict. As a sequel to From the Shadows, this module gives the player characters an oppurtunity to atone for the evil they unwittingly caused as pawns of Azalin. The culmination of a six-part series of adventures dealing with the Grand Conjunction, Roots of Evil gives the player characters an oppurtunity to literally save the universe (as well as themselves!).
Until the dark powers recapture the lords of Ravenloft, no place is safe...."