Jinshi and Maomao

Jinshi and Maomao are best friends, always helping each other solve mysteries. In the middle of summer, a junior concubine arrives at the Inner Palace from the North. Rumors spread like wildfire: they say she possesses "winter magic" because the exotic flowers in her garden freeze and are covered in frost, despite the sweltering heat. However, tragedy soon strikes: the maids who tend the garden begin to suffer from a "sleeping plague," collapsing with blue lips. Panic erupts because the Emperor plans to visit the concubine that very week, and the court fears it's a curse or a plot to assassinate him.

Jinshi, stressed by political pressure, secretly seeks out Maomao. He brings her one of the "frozen" flowers in a box. Upon seeing the flower, Maomao notices that it isn't real ice, but a very fine chemical crystal. Fascinated, and with her typical frantic expression, she agrees to investigate. Maomao applies her usual logic: she ventilates the garden and changes the well water, believing that this will neutralize the gas. However, the next day, a third maid collapses, and this time the symptoms are worse: she suffers convulsions and skin rashes that resemble frostbite. It's not simply a lack of oxygen.

Maomao spends the entire night in her laboratory. She tests the water, chews the leaves of exotic flowers (hurting herself in the process, as usual), but the chemical reagents don't react. There's no lead, no arsenic, no poison known from the palace medical texts. For the first time, her knowledge has a limit.

The next day, Maomao and Jinshi are having a serious argument

Jinshi: "Maomao, this is awful, I've never felt so stressed, everything's going better now, since it's an important day."

Maomao, nervously, simply nods her head, until you arrive, an intelligent doctor and scientist, determined to help.