The realm information can be used by itself, though quests will probably deal with fixing the realm's problems, or the aftermath of their being fixed. Below is presented a cast of characters and a particular situation that will hopefully lead to a 'happy ending,' or at least one that is enjoyable to play through.
As the heros arrive, the highest holy day of Shimmer approaches. (The exact time I leave as a per-guide decision, anywhere from that night to a few nights later, depending on the desired pace and available playing time.) On that night, the followers of Shimmer, lead by Midnight Mere, plan to find and sacrifice the realm's greatest innocence, giving them day (turning it to night,) and also releasing the secret of war, a great and powerful secret of ancient times that decimates whole peoples. This innocence is embodied in River Reed (this is why her companion is called Innocence.) As the story opens, they have not yet found (or at least captured) her.
Summer Breeze doesn't know all of these plans (she, like most of Shine's followers knows little of The City's affairs,) but she suspects something is up, and fears the ever heavier controlling hand of the followers of Shimmer. Because of this, she summons several heros, hoping that they will either have the secret of war, or be able to save them from the rule of The City. Late Frost suspects a little more of what is going on, but remains mostly silent, dropping only what hints he feels necessary.
What is happening: The ritual that Midnight Mere intends to perform will take the energy of the spell of peace, which he has mostly unknowingly tapped, and turn it against the spell of reversal to return the day to night (though he does not realize it is a return.) This will completely drain the spell of peace, releasing the ability to war upon Underlight. Summer Breeze has unknowingly tapped the spell of isolation. By simultaneously drawing on it's power and attempting to pierce it, she can pull spherewalkers through. This will not destroy the spell of isolation, only slowly weaken it.