Edward Grainger has been asked to meet a representative of the British government. The man, who calls himself "the Professor", recruits Edward for a mission to China. In China, they infiltrate the Zhong Ma camp, where Edward learns from the Doctor that the camp is used by the Japanese for the purpose of experimenting on humans. Edward and the Professor are here to rescue Mai Ling, an old friend of Edward's.
Edward and the Professor are captured and put in separate cells. Edward's cellmate is horribly ill and eventually dies from the Bubonic plague, which was purposely inflicted on him by his captors. Edward contracts the disease as well.
He is rescued by the Professor, and they split up: Edward is to rescue Mai Ling, while the Professor must destroy the samples of blood that the Japanese took from him.
On their way out of the camp, they are accosted by guards, but they escape when the guards are afraid of catching Edward's illness and retreat in fear. The Professor and Edward and return Mai Ling to her husband.
When Edward recovers from his illness, he finds two letters: one from the Professor, telling him not to search out Mai Ling, and one from the British government, inviting him to be an operative for them — in secret for now, but officially when the inevitable war takes place.
to be added
- The stories in Short Trips: The Centenarian revolve around Edward Grainger, a man who has met the Doctor more than a dozen times over the course of his life.