A wizard claims to have developed a spell which will not only protect people outside the Golden Cities from the effects of the Bunanj, the two mesters during which most people turn temporarily into metal statues while undead roam the world, but will also draw power from these mestral effects and use them to grant great boons to those affected. Just before the outset of Gurunda, the first mester of the Bunanj, he casts the spell on some willing volunteers, promising that afterward the subjects will not only be healthier than ever, but will have additional magical abilities due to the effects of the spell, and will remember and be able to relate their experience during these mesters when everyone else is a statue.
That isn't what happens—apparently the wizard made some mistakes in his creation of the spell. When everyone else (including the PCs) returns to flesh and consciousness after the Bunanj, they find that the volunteers have been mutated into horrible monsters and have been—and still are—on a rampage through the area. Obviously they have to be stopped, but killing the mutated individuals isn't the ideal solution—first, because they were innocent people and it might be possible to return them to what they were, but also because some people and important objects are missing and some things have changed in strange ways, and it's important to find out from the mutants, if they were really awake during the Bunanj what they were doing during this period when everyone else was inanimate, and what happened to the missing people.
