A dying man turns up at Eric Besson's office, carrying a notebook full of investment records. For decades he has been helping Paris' dirty cops launder stolen money, and is adamant that Besson get the notebook to Paris's chief prosecuting attorney so the corruption can finally be brought to light. But Besson's assistant - his nephew - is murdered en route, and the notebook disappears. Grief-stricken Besson tries to hire Aimee Leduc to find it, but she is reluctant to get involved. She's not sure which she's more afraid of; the men who would kill for the book, or the idea that her father's name might be among the dirty cops listed within it.