This is a Fallen London exceptional story, meaning it is a supplementary tale to the overall main game.
This story was meant to explore the bone market and its side characters more. When the bone market first came out, the Carpenter's Granddaughter was (and is) an important figure who can sell the largest bone frame and manage your market exhaustion.
In this story, you go on a journey with that character to the Gant Pole, a location first featured in the spinoff game Sunless Sea. The Gant Pole is an enormous decomposing heart of a sea creature that is lived in an attracts things that have lost all other desires or purposes in life. Gant is one of seven fictional colors in Fallen London, described as the color that exists when all else is gone.
As you search for giant bones and fossils in this story, it takes a darker turn into body horror, including a chance for you to alter yourself in disconcerting ways.
Overall, this story is an interesting character study of its main protagonist and antagonist. The interactivity aids the story but isn't memorable in and of itself. A good option for fans of the Zee and/or bones.