Kakeru Endo, a farmer from Hokkaido, is suddenly transported to another world while taking a bath one day! In this new world, the breast milk of magical beasts is a powerful energy source used for all kinds of tools and weapons, sustaining the lives of the common folk. These warriors who gather the magical beast milk are called "Milk Hunters." However, the number of Milk Hunters is few, and the supply of milk is running dry in every country. To help alleviate this milk crisis, Kakeru is summoned from his world as a Milk Hunter.

Using the milking skills he learned on his farm with cows, he must arouse magical beasts to collect fresh milk and save the world from its dire situation!