This one.

ObTrav: The PCs are contracted by one of the Imperial High Nobles with jurisdiction over a mid-tech world with such a star. The world in question has only limited experience with interstellar contact and most of has been pretty awful (cough/-megacorps-/cough). This past experience makes conducting an open campaign to convince the population of the seriousness of this very-slow-motion crisis problematic. How the PCs handle their task is left pretty much up to them, but the noble stresses that off-worlders can't be seen to be involved.

And - of course - there are interstellar interests which wish to create (for various reasons of their own) a state of unreasoning panic among the general population, rather than a reasoned response.