A Flow be Sealed, and none shall harm; let groundling kingdoms lie.
A Flow be Free, then ’jammers reign, and ships shall fill the sky.
But when the Flow be Sundered whole, doom sounds its toll-bell nigh;
For groundling and ’jammer alike shall race, and all the peoples die.
—From the Prophecies of the Spelljammer, Temple of Bihali
This is the tale of great transformations. Some worlds have Sealed Flows, protected against the interference of spelljamming culture. Others are Open Flows, part of the great trans-Spherical community of spelljammers. One is either one, or the other. No one has ever heard of a Free Flow being Sealed, or a Sealed Flow being Opened.
Until now. It was a dark day when a company of innocent adventurers fought their way into the inner sanctum of the Temple of Stars, beneath the city of Blackwall, on the opalescent world with a Sealed Flow in the Sphere of Gems. But they snatched the gem there, and released the great beam of light, which flowed up into the sky and pulled down a great stone hatchery filled with deadly beholders.
It did more than simply unleash a many-eyed doom upon the city of Blackwall, destroying it. It also somehow tore a great tattered hole into the Flow of this world, called Opal by spelljammers.
And now a small party of adventurers – the very one responsible for the doom of Opal’s Flow and the city of Blackwall alike – is setting first feet into the treacherous wildspace beyond their home. Will they flee their home like so many groundlings who find their way into wildspace, or will they work to save their homeworld from the terrible fate that awaits it?