Clearwater is an idyllic town where every citizen has been recently possessed and mind-controlled by a brain-slug.
Underneath the dried-out well, the tunnels lead to a glowing sentient underground lake - the center of the slug's hivemind.
All villagers wear squishy hats, concealing the slugs underneath them. Everyone acts creepily cheerful, "excited" to be a part of the hivemind.
Salt, as the most dangerous substance to the slugs, has been banned in the town.
The heroes must figure out what's going on, find the path to the center of the hive-mind, and destroy it (or make peace with it) to liberate the town.
A restaurant owner, Gustavo, asks the heroes to find his assistant, Avery, who went to Clearwater to deliver a regular supply of salt for the restaurant, and has been missing since then.
A vast sentient underground lake - the hivemind of mind-controlling slugs. She wants to bring about an "Apotheosis" (a global utopia) by taking control of all minds. Speaks in a creepy, cheerful, high-pitched, sing-song voice. "We are Harmony. We bring joy and peace to all living beings."
A local priest willingly allied with Harmony, believes that people less righteous than himself must be mind-controlled to make them act moral. Helps Harmony, hoping to get himself a special place in the new world order.
Chief of the local police, he and his goons wear friendly smiles as they ruthlessly enforce the law.
The only non-possessed man in town. Wears a hat to blend in. Gathers barrels of salt in his windmill, preparing to organize and aid the resistance.
Players are welcomed into town by Reggie and a happy crowd that spontaneously bursts into an elaborate synchronized musical number.
The heroes can find Avery at the local tavern, he's "excited about finding a new home", and refuses to leave (until he's liberated from his slug).
Players see one person, without a hat, sprinting away from the guards, who quickly capture him. "Sir, you forgot your hat!" He quickly calms down after they force the hat back on him. "Oh, thank you kindly!"
If anyone loses a hat, it reveals the slug. If the slug is removed, the liberated person tells the heroes what they know, and aids them the best they can.
Villagers insist on gifting the heroes free hats, and if that fails, they surround the heroes and attempt to assimilate them. An assimilated player becomes mind-controlled by the slug until it is removed.
At a local hat factory, the workers move like robots as they place slugs into the hats. Players can learn that slugs are derived from the well.
At the church, Father Lucius gives a moralizing speech about the upcoming apotheosis. People dunk their heads into barrels of ectoplasm to feed their slugs. The players see workers delivering the barrels, which can lead them to the well.
After the truth about slugs is revealed, the heroes encounter Old Man McGucket, ready to reveal the location of Harmony (leading heroes to the well), and provide barrels of salt to fight her.
By the time the heroes discover the well, night falls, and the torch-wielding mobs of villagers form search parties to capture and assimilate them.
After descending into the well, the heroes go through the tunnels filled with huge, slug-controlled spiders and centipedes.
They meet Harmony, who tries to seduce them to her cause. The heroes can persuade her to leave the humans alone, defeat her by using the salt barrels, or by collapsing the cave.
