You are sitting in a bar when...
A codex to collect great campaign starters!
As a part of each characters background, one of these stones becomes their birthright. The campaign begins after they have been drawn together and happened to be present when
The PCs are part of an effort to track down and capture/destroy the various baddies spawned by the starfall. They then come to find these are simply the heralds for a much greater world-shaking event that they need to stop.