Farma accompanies his father Bruno on his house call to the Empress. He realizes he has the ability to cure her, but he can't do so without drawing attention that would put him in jeopardy.

Farma continues to treat Empress Élisabeth II, which leads to an unexpected reward.

Farma reaches the capital only to find that plague is spreading swiftly through the city. Can he and the people of the capital get the situation under control and defeat this epidemic?