An Extraordinary Union by Alyssa Cole 

Elle Burns is a former slave with a passion for justice and an eidetic memory. Trading in her life of freedom in Massachusetts, she returns to the indignity of slavery in the South—to spy for the Union Army.

Malcolm McCall is a detective for Pinkerton’s Secret Service. Subterfuge is his calling, but he’s facing his deadliest mission yet—risking his life to infiltrate a Rebel enclave in Virginia… Read more.