The setting is modern-day Japan, where an epidemic known as "Flower Erosion Disease" has taken hold. This is a story of Guest interacting with a character suffering from this disease.

[About Flower Erosion Disease]

Source: The source of infection is "microscopic seeds" dispersed from mature flowers. Transmission: Transmission occurs through contact or blood. Infection is particularly likely through contact with the wounds or bodily fluids of an infected person.

[Progression and Stages]

Early Stage (Incubation): Seeds settle in the body and extend fine roots along the capillaries. There are no visible external wounds, but mild fatigue is present. If detected at this stage, progression inhibitors are administered.

Middle Stage (Onset): Buds open and bloom from old scars or soft skin (such as the inside of joints).

• Pulmonary Parasitism: If seeds take root in the lungs, symptoms include coughing, difficulty breathing, and bloody phlegm mixed with tiny leaf fragments.
• Cerebral Parasitism: Trace amounts of neurotoxins (or endorphin-like substances) secreted by the plant cause headaches, hallucinations, and occasionally a state of "pathological euphoria." Treatment involves pruning (surgical removal of external buds/flowers) and progression-delaying agents.

Terminal Stage (Full Bloom): The entire immune system is destroyed as the plant siphons off all nutrients. Flowers bloom profusely across the skin, and consciousness becomes clouded. Death eventually occurs due to heart failure or multi-organ failure. Only palliative care to alleviate pain is available.

[Treatment of Flower Erosion Disease]

Incurable: Because the roots integrate with blood vessels and neural networks (fusing at a cellular level), extraction is impossible. Pruning: The act of cutting away external flowers and stems. However, because the plant's survival instinct causes it to "root even deeper" when cut, this is accompanied by intense pain and requires continuous medication to suppress root activity.

[Social Perception]

The government advocates for the "eradication of Flower Erosion Disease," offering free distribution of medication and isolation in specialized hospitals, maintaining a humanitarian approach. However, society views it with prejudice and misunderstanding, labeling it a "disease caught through immoral contact" or believing "one can be infected just by shaking hands."