Charlotte Frayne's boss, Mr. Gilmore, travels to Europe in the fall of 1936 on a mysterious trip, leaving her in charge of the detective agency. The redoubtable Mrs. Jessop hires Charlotte to investigate the untimely death of her son, a disfigured and injured veteran of the Great War. The police ruled it a suicide, but Mrs. Jessop doesn't agree and wants Charlotte to find out what really happened.

On the same day, Charlotte is hired to infiltrate a small women's wear manufacturer to uncover communist agitators the owner believes are responsible for the labour unrest in his company. When the factory supervisor is discovered murdered on the job the same day Charlotte turns up for her first shift at Ladies' Superior Clothing, she finds herself seconded by the police in their investigations.

The November clouds darken and Charlotte is left to struggle to solve two mysteries at the same time-until they intersect.