Once upon a time, the ruler of the town, which is located further along the river, hid here. It's a secret, but he had a plan to take revenge on his enemies if they captured his city. He planned to poison the river until the town died out.
His plans were not destined to come true, and the stronghold was abandoned and became flooded ruins when the source intensified.
More recently, information has been discovered that large reserves of poison are hidden somewhere in the ruins. Who will get this poison faster? Residents of the city or its enemy?