Foul Lady Fortune

From the #1 New York Times bestselling author of These Violent Delights and Our Violent Ends comes the first book in a captivating new duology following an ill-matched pair of spies posing as a married couple to investigate a series of brutal murders in 1930s Shanghai.
It's 1931 in Shanghai, and the stage is set for a new decade of intrigue.
Four years ago, Rosalind Lang was brought back from the brink of death, but the strange experiment that saved her also stopped her from sleeping and aging—and allows her to heal from any wound. In short, Rosalind cannot die. Now, desperate for redemption for her traitorous past, she uses her abilities as an assassin for her country.
Code name: Fortune.
But when the Japanese Imperial Army begins its invasion march, Rosalind's mission pivots. A series of murders is causing unrest in Shanghai, and the Japanese are under suspicion. Rosalind's new orders are to infiltrate foreign society...