The Yucatan Mercenary Nation, a military republic from the Far West, is hired by Nuova Roma to clear the island of Corse and smoke out any remaining Holy Romagna holdouts. Over the next month of sustained combat, the Yucatan Mercenaries liberate Corse's settlements from the Roman Inquisition, and make a horrifying discovery: the 'Savonarola Measure', a chemical compound with the power to melt any organic matter into a rancid biofuel slurry.

Refusing to let Nuova Roma have such a powerful superweapon, the Yucatan Mercenaries keep the island of Corse for themselves, along with all the research and processing facilities related to the Savonarola Measure. However, Jose Galan, a Roman spy masquerading as a Catalonian liaison, steals a sample of the compound, putting its power in Nuova Roma's hands regardless.