The universe is filled with ether, and various planetary nations build their own cultures in the "Star Systems". One day, a foreign object got mixed in.
It was the super-large immigrant ship "Jena" that came from the universe outside the Star Systems. Jena called itself the "Jena Federation" and expanded by absorbing small planetary nations in the Star Systems one after another, and quickly began to have a great influence on the world.
However, the Jena Federation, which had reached the height of its glory, suddenly fell into chaos.
The death of its absolute charismatic leader.
As various intentions intersect, a fierce battle for succession between the top executives of the Jena Federation was about to begin.
Once Upon a Time in Phlogiston is an simultaneously action selection worker placement game in which players become the top executives of the mafia nation Jena, gather allies, travel the universe, increase work, and contribute to the organization in order to win the battle for succession.