by August Derleth Originally published Travellers By Night, Arkham House 1967
1948. Ambrose Bishop inherits yet-another property in Dunwich, previously the residence of yet-another great uncle, Septimus Bishop, who vanished 19 years before. The place is undisturbed - there's even books and papers lying around on the tables. There is a mildew problem, though.
The townsfolk are rude as usual, including the ubiquitous Tobias Whateley, who won't even sell him goods, and tells him Septimus was murdered by his neighbors, who now won't set foot on the property. Ambrose begins to investigate. All he finds is that Septimus disappeared, and at the same time someone strengthened one of the piers in a disused bridge along the Miskatonic, but the county denies any involvement.
Back at the house, Ambrose finds some astrological texts, a telescope, some weird symbols, and, in the basement, a flight of stairs leading into the earth. This leads into a circular chamber with an altar, and lets out in a concealed trapdoor in the woods, near the aforementioned bridge. There is also a third door in the tunnels which Ambrose opts not to open - yet.
Going through unc's papers, he finds some letters from the Starry Wisom cult, and a letter from Wilbur Whateley himself, rehashing some bits from "The Dunwich Horror". And stories of children going missing from the area.
A storm collapses the bridge, including the patched-up area (which happened to include some five-pointed stars). Ambrose checks out the area, an collects some bones that he finds scattered in the water. And takes them home for no apparent reason. Where they promptly disappear.
Ambrose searches fruitlessly. That night, he dreams of the bones reassembling themselves into his uncle, and of a creature that shapechanges from black cat to octopoid monster, to giant sow to indescribable to a "lissome naked woman". Waking up, he sees Septimus and the mysterious companion walking off into the woods. So ... he goes back to sleep.
In the morning, he finds fresh footprints leading to the altar room, and fresh blood on the altar. And uncle Septimus and his "familiar" show up in the house.
A few days later, kids start disappearing again. Ambrose finds evidence of their demise in the altar room. The locals storm the house and burn it down. Ambrose hides with Septimus in the tunnels, leaving behind a manuscript relating this tale. The locals rebuild the collapsed pier, and re-inscribe it with star-symbols.
