Chartered in Royal Year 618, the Guild of Adventurers Upon Return, was intended as a guideline to deal with and control the increasing number of men and women who were taking up arms and pursuing a career in heroism and adventurism. The guild would police it's own, and function as an odd jobs mercenary corporation, subservient to the crown, and supportive of the clerics.
The secret for immortality has been discovered by an eccentric wizard/mad scientist. Its found you need to reapply once a month. As people stop dying, and the birth rate increases exponentially, people are forced into homelessness, because of the need for food reamins the same, and food is not being produced fast enough to feed the undying population. The PCs have to find the creator and kill him, and destroy production, to save the world from undying, unending torture from hungryness.