Example character:
Plot1: Negotiation of kingdom X for increased trade

Chance:
Keep an eye out for signs that anyone is meddling with planar barriers, or that such barriers have weakened.
Pursue current lead: a gnome who travels the wilds on the back of a small unicorn has been asking questions and making observations about a conjunction in the sky.
Ask NPCs and search locations for signs of planar malfeasance.

Party:
Avoid, in their various activities, bringing themselves to the attention of the local power, which consists of one or more of:

Who would like to

the PCs.

Obtain information. This information is necessary to:

And it is located