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.
A terrible teleportation incident makes inter-demihuman chimaera of all the PCs. Quoth Master Adams: 'I teleported home one night / with Ron and Sid and Meg / Ron stole Meg's heart away / and I got Sidney's leg.'
It has been said that within the mountains (or was it the darklands?) there dwells a fluffy creature of immense cuteness. This creature is so adorable that all who encounter it are filled with joy so great their mortal forms cannot contain it. And they explode. Several magic institutions are desperate to study the creature or better yet capture one to prove the theory of an elemental plane of "D'Awwww".