Act I

Act I was the first part of The First Horseman, focusing on the beginning of the assassinations carried out against the clergy of the Church of Sol and the party's initial discoveries about them, leading into Act II when the party acts on these discoveries. The discoveries themselves aren't expanded on until Act III, when they're revealed to be false.

Prologue
Once shining with the light of Sól, the vaunted halls of Caer Sól have grown dark. Where priests once chanted sacred hymns, where knights in shining armor once clashed blades in training, eldritch invocations and fiendish howls now resound through the ancient city, their voices like a rising cacophony, the thunder of a bleak storm.

Three priests stepped quietly through the gallery, each robed in black, each with a necklace around their withered necks. A white-haired, aging priest wore a necklace of a four-horned goat head. A dark-haired, youthful priest wore a necklace of a demonic face, surrounded by slithering snakes. The third, their leader, a sickly, horned woman, wore the symbol of a pair of bloody wings.

“The lore within these halls could fill our archives tenfold,” began the older priest, motioning to the tall bookshelves, surrounding him at every side. “We have only just begun, yet our plans are already nearing fruition.”

“Yes,” whispered the young priest in a shrill voice. “Thank the Master of Final Incantation,” he said, caressing the symbol around his neck.

The old priest stifled a laugh. “Thank the Prince of Undeath. Thank him for allowing the Shadowmaker to ascend to the black throne. And thank the old lich that he has allowed us to prosper here, rather than throwing us to the Abyss. We are fortunate it is us allowed, and not one of his… pupils.” “Enough,” said the priestess. “There are specters here who would hear us.”

“Specters? The sun god has no power here. Look around you,” answered the young priest. He was right. The world had not seen the sunrise in centuries.

“Not of the sun god,” she answered, and the boy was quiet.

The priests entered a circular hall, with a great stone table. Seven stone chairs surrounded the slab.

''The priestess held her symbol in her hand. “Las sra kim krema em srek rorr, ku sros va koae roc sra ki’k kacrask,” she whispered, and the floor moved beneath them.''

Stones shifted from the black chasm that had formed, and a staircase fell into place as the priests continued, down, below Caer Sól. “The final piece is here. And then we shall sunder Frey.”

They entered into a great, stone area. Tapestries lined the walls, now defaced with the symbols of their dark gods. A great noise, like the beating of a drum, filled their ears, louder than the whispers of the gathered congregation. At the center of the room was a bloodied, stone table. The bleeding body of a man dressed in the garb of a priest laid upon the slab, and sat upon his form was a book.

The priests took their place at the center of the room.

“Let us begin,” said the priestess, and the beating stopped.

First came the sound of a screech, more like a dragon’s roar than an eagle’s cry. Then came the sound of breaking. Like stone tumbling, great pieces of something were being torn away. The cry came again, louder, muffled before.

Then it was as if the whole city was quaking, as though Frey itself was shaking, nervously preparing to accept whatever came next. The floor fell out around the congregation, disintegrating into tiny pieces as though stone was being burned away. The three priests were standing on an island above an ocean of light, a blinding white chasm.

Then came the noise of beating wings, and the thing came up to greet the intruders. The phoenix, like a bird forged from fire. And then it unveiled its burning talons, and all was white.

Under the bright light of Sól, three amulets fell to the cracked ground.

Summary
The party arrived in Blackbridge to answer the call of adventure - Father Tihomir, parish priest of the village, had gone missing en route to Newstone, delivering plague relief to the scourged hamlet. They joined with Raiwen Talethar, a student of Bregate's Arcane Academy, standing up to a group of racist bullies for the elf-mage before meeting with Tihomir's replacement, a priest named Anselm, who himself was meeting with the mysterious Tegwen the Enchantress, who seemed interested in the priest and the party's mission. In the great forests of the Wosswood, the party found Tihomir's corpse strewn among the wreckage of his wagon. They tracked the assassin to the nearby Lost Crypt, where he had been slain by its goblin inhabitants; pursuing the goblins through the crypt, they learned that their leader, Nagzem, reported to Goblin King Sorzek and had given him the assassin's amulet, leaving the heroes with nothing else to identify the assassin. Meanwhile, the party learned that the crypt - host to the body of Lusalor, a paladin who died defending the Seal - was once home to Corellonite clergy, whose ghosts granted them a boon in return for the tomb's cleansing, as well as the sword of the tomb's prime occupant, Orc's Lament. They found the plague supplies, and took them to the ruined village of Newstone, where they learned that encroaching humanoids - kobolds, namely - had invaded and stolen away with prisoners.

The party crossed the Wosswood, eventually seeking out Mt. Rann, where a door in the mountain lead to the dark Dwarven Crucible, which they found infested with goblins, hobgoblins, and bugbears. Within its walls, they slew and battled Afon, a Wraemorite agent seeking to release something called the Emerald Terror. The party slew its guards and battled a dangerous manticore and a powerful goblin witch before facing off against Sorzek himself. Sorzek revealed himself to be the only thing stopping the Kobold King, Yiktaz, from accessing the Seal - a powerful magical effect sealing the Emerald Terror, Malaemarux, within Mt. Rann. The party agreed to retrieve Yiktaz's head in exchange for the assassin's amulet, to the frustration of one of the prisoners of the Crucible, Strommuth Bronzebrand, who departed, but not before Aldus instructed him to return and retake the Crucible.

The party pursued the kobolds to their lair in the Shambling Temple, a three-winged temple to three different demon lords - Deskari, Orcus, and Abraxas. At the entrance to its crumbling ruins, the inquisitor Aldus was slain before he could reveal what he had spoken to Strommuth about. The party retreated and recruited Silas Rooke before returning to the wicked temple. Within its crumbling ruins, they completed Raiwen's quest in finding the Abyss leaves of the Malgarian Tree; they faced off against the incubus Becuriel, summoned aeons ago by the temple's ancient mistress, and accidentally freed him from his prison; they found ancient demonic lore, and slew the Kobold King, who had used the foul magic of the temple and the souls of the prisoners he had taken to turn himself into a half-fiend. With Yiktaz slain, the party returned to the Crucible, where Sorzek completed their trade, giving them the amulet, inscribed with a sinister nine-pointed star.

In Blackbridge, Father Anselm confirmed their suspicions, explaining that the Nine-Pointed Star is both the sigil of the Infernal Pact and the name of their vaunted and mysterious leadership. With Bregate being host to the largest population of the cultists in Noslith, Anselm instructed them to meet with Solveig, a dame of the White Rose, in the old city, to join her in her fight against the diabolic cult, learn why the Infernal Pact is killing priests, and bring the light's justice down upon them.