“ The villages around the capital have a strange new disease cropping up. Spread by a fungus (much like ergot poisoning), it causes its victims to be very sensitive to sunlight. Hundreds of peasants are hiding from the sun, only coming out in the darkness to labor in the fields. Unfortunately, rumor makes their behavior sound more sinister and secretive than it really is.”
“ 'Binding the Life Coil' is an ancient quasi-mystical technique rediscovered to prolong one's life at the expense of one reproductive ability. It is a simple magikal technique that anyone can learn (a skill or feat). The promise of near immortality or a lifespan of a thousand years or more makes everyone want to learn it.
This technique has a price though, the amount of immortality is in direct response to the strength of ones reproductive spirit. Those that have never breed will live longer than those that have. The use of the technique makes conception difficult, if not impossible. So you trade the future of your society for the chance for you to see much of that future.”
“ The PCs are accosted in a major city containing at least one famous fortuneteller / prophet of the future. They are informed that their as-yet-unborn child will (insert terrible evil), and that, although they are very sorry, the PC must be executed to keep this from happening.”