In Biggles in the Gobi, Miss Treves was one of the refugee missionaries whom Biggles was sent to rescue from Western China. Miss Treves, an young Englishwoman, had hidden in the caves of Nan-hu with her older colleague Miss Summers and 9 other missionaries.
When Nan-hu had been attacked by the troops belonging to Colonel Ma Chang, most of the missionaries had been captured or killed. However, Miss Treves, Miss Summers, Mr Ritzen and Father Dubron had escaped capture and were on hand to meet Algy and Ginger on their arrival at Nan-hu.
At the end of the book, she was among the people safely airlifted out when Biggles arrived at Nan-hu with the Halifax.