A unique spear that was lost in production.
An instrument that that transmits feelings.
Sharp as a sword, light as a dagger, and easily concealable.
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.