The year is 4357
And everything is definitely not what it seems at Benden Weyr! With the changing of the seasons from Summer to Fall in late 4350, a strange convergence of wind, sea and pure happenstance left a strange spherical anomaly just off the coast of a small fishercraft hold. The anomaly, later known as the Waypoint, would prove to be something the bewildered fisherman would understand as a 'doorway.' Urgently, they contacted the dragonriders in Benden Weyr, where three of the mighty Threadfighter Wings were in permanent residence.
The responding rider, a Wingleader of some renown, realized that the situation was drastically above her paygrade - but was equally aware that she couldn't start a panic as the first decidedly non Pernese dragon emerged from the anomaly. That 'rider' turned out to not be a 'rider' in the Pernese sense at all. He, like the great silver beast he accompanied, was a refugee of war.
Perhaps it was providence, or perhaps just sheer dumb luck, but the Wingleader had spent her formative years diving among the histories of Earth preserved in the AIVAS archives. Armed with some knowledge of the concept of violence - as well as enough good sense to recognize a humanitarian mission when she saw one, she granted the pair temporary refuge in the cliffs near the anomaly. The fisherfolk were perplexed, but the silver beast had powers unknown to Pern, and with a brush of thought - the holderfolk thought no more of her then the sand on the beach.
Over time, more refugees arrived. A proper arrangement and a proper settlement was required - all of which were organized by the Wingleader and the Senior Queen of Fort Weyr.
The price, however, was complete secrecy. Pern would shelter those tossed through the Waypoint - but in return they would ensure that Pern itself remained untouched and unchanged by their strange magic and even stranger ways.
Time will tell whether this understanding will hold.