Captain Chin Lee was a Chinese army officer and General Cheng Teik's aide when he was the Chinese delegate to the World Peace Conference. While at an embassy reception, she met the Master, who was posing as Professor Emil Keller, and accepted his invitation to see the Keller Machine at Stangmoor Prison. While there, he hypnotised her and used her to sabotage the Conference, including stealing and destroying state documents, killing the General and attempting to kill Senator Alcott. After the Doctor stopped her from killing the Senator, he questioned her and learned of the Master's connection. (DW: The Mind of Evil)