When a German businesswoman in 1979 San Francisco hires ex-con PI Colleen Hayes to find a missing relative, supposedly in town to visit, she thinks it's a simple job. But she soon discovers that the "nephew" is linked to an international vigilante group hunting down ex-Nazis. Then the body of a mysterious woman turns up on San Francisco's Municipal Railway, mirroring a murder committed the week before in Buenos Aires where the "nephew" had just been. Colleen's search uncovers a World War II banknote and the 1942 SS ID of a German officer long thought dead. When Colleen fails to heed warnings to stop her investigation, her pregnant daughter is attacked. The so-called nephew is nowhere to be found. The German businesswoman has fled town. Colleen's search leads her to Italy where the infamous Vatican Ratlines helped escaped ex-Nazis forge new identities around the globe. Deep in the Italian Alps, she uncovers a secret project hatched in a concentration camp. Colleen has no choice but to push ahead if the killing is to stop and justice prevail.