The PCs’ immediate boss Assistant chief Inspector Stover Delft orders them to provide extra security for the Kaybeau Arms and Technology Exposition. The PCs are present when strange monsters unknown to modern scholarship appear and attack fair-goers. After killing the monsters, the party learns that the creatures were summoned by an ancient magic staff made of solid gold, which a fair-goer had purchased on the black market.
Only a day into their investigation, the party learns that lord Viscount Inspector Nigel Price-Hill, national director of the RHC, is coming to Flint to oversee an audit of the local branch. PCs who have been cutting corners, breaking the law, or failing to hand over evidence so they could keep it for themselves will have to scramble to avoid punishment.
Through a string of contacts, the party tracks the sale of the staff to Kaja Stewart, who stole the relic and several others from Macbannin’s manor. If arrested, she dies soon thereafter, the victim of a fake suicide in jail. Crime boss Lorcan Kell pursues the PCs for harassing his business partner, and various minor threats from the expo keep them busy, but eventually the party connects the relics to Pardwight University.
Hans Weber, the curator of Pardwight’s natural history museum, is planning a gala of artifacts of the Ancients, and he can put the PCs in contact with Dr. Xambria Meredith.
Xambria recalls finding the staff at the site of her last expedition, but she claims she was away when disaster struck and all of her cohorts were killed. She suggests the party find Caius Bergeron, who sponsored her dig, then vanished after the disaster. When Caius claims to be a harmless philanthropist, however, the PCs have few options left other than to head to the dig site and scour it for clues.
At the ancient ziggurat, the party must avoid dangerous traps and battle strange creatures from another world. They find the bodies of Xambria’s expedition, as well as a group of specialists who had been sent by Caius Bergeron. The golden seal is missing, and a map in the ziggurat points to another possible dig site.
Their presence draws the interest of a long-slumbering fey titan, the serpentine Voice of rot, who believes the lands around the ziggurat are his domain. He tells the party that an interloper from another world escaped the ziggurat, and that he will punish the mortals in his realm if they do not deal with the intruder for him. The party can use magic to track the foreign planar energy trail left by the creature, which leads them back to Flint.
The trail of planar energy criss-crosses itself and leads to several red herrings, but also goes to Xambria’s home, where there are signs of a struggle, but no sign of the woman. The trail also points to Caius’s inn, where the PCs find that he has been murdered, and his brain has been devoured. While searching his room for evidence, they learn that Caius sent an expedition to the dig site marked on the map in the ziggurat, off the coast of Ber, several hundred miles away.
Chasing the second expedition, the PCs reach Ber and find three ships in a stand-off. One is owned by Caius, and it tries to protect a group working to open the seal, which is underwater. The second is a Beran archaeology vessel, while the third is a boat Xambria chartered. She claims she was attacked back in Flint, and that she headed for this site, hoping to stop Caius’s team before they unleashed more monsters.
The energy trail points to Xambria, though she can explain this away because she has been wearing the golden icon of Apet, which she recovered at the first dig site. She plays the frightened innocent, but in truth she has fallen under control of Sijhen. After the party defeats Caius’s team, Sijhen bides its time, then distracts the party by summoning monsters. During the disturbance, Sijhen devours the brains of any prisoners, steals the ritual book they used to open the seal, and flees via teleportation.
When the PCs get back to Flint, Pardwight curator Hans Weber asks them to protect the Ancients gala. Xambria attacks the event with a host of monsters, and she tries to steal relics from the ziggurat of Apet. Even if she obtains them, however, she lets the PCs defeat her and quickly surrenders.
This is part of Sijhen’s gambit. To get home, it hopes to open a portal to Gidim. But to properly aim that portal, it needs an Ancient star map. Lady Saxby just happened to confiscate one after the downfall of Macbannin, and she keeps it locked up in her office in the RHC headquarters.
Xambria stages her own capture so she’ll be brought to the headquarters, and so Saxby will be present. Before her capture, Xambria sends word to the Obscurati that Saxby is planning to turn on them, and so the Ob sends assassins to silence the Chief Inspectress.
Sijhen wants to consume Saxby’s brain, as well as those of the assassins, since it plans to return to this world eventually, and wants more knowledge about the Obscurati. It isn’t afraid of the mere mortals who stand in its way, but it doesn’t realize that the Axis Seal will utterly thwart its attempts to go home.
Shortly after the PCs lock up Xambria in an RHC jail cell, she springs her trap. Using a makeshift portal, monsters and reality-warping energies from Apet pour into the building, letting Xambria escape. She heads for Saxby’s office as assassins make their move, all while the other staff of the headquarters are driven mad and turn on each other.
The party must rush to avert several catastrophes, and when they confront Xambria at her portal, a mishap unleashes a massive warbeast, long ago bred by the Gidim and trapped on Apet. To kill it or drive it back, the PCs might have to form a temporarily alliance with Sijhen itself, or else they’ll all be killed.