"A murder in wartime Switzerland reveals Swiss complicity with the Nazis and profiteering during World War II Billy and Kaz are sent to neutral Switzerland to investigate the murder of a Swiss banking official with ties to the Office of Strategic Services (OSS). The US and Swiss governments are about to embark on diplomatic discussions regarding the Safehaven Protocols, which are aimed at limiting the amount of war materials exported by Switzerland...

"Lieutenant Billy Boyle could have used a rest after his last case, but when his girlfriend, Diana Seaton, a British spy, goes missing in the Vatican, where she was working undercover, he insists on being assigned to a murder investigation there so he can try to help her. An American monsignor is found murdered at the foot of Death's Door, one of the five entrances to Saint Peter's Basilica. Wild Bill Donovan, head of the OSS, wants the killing investigated....

"1943: In the midst of the brutal, hard-fought Solomon Islands campaign between the Allies and the Japanese forces, Lieutenant Billy Boyle receives an odd assignment: he's sent by the powerful Kennedy family to investigate a murder in which PT skipper (and future president) Jack Kennedy has been implicated. The victim is a native coastwatcher, an allied intelligence operative, whom Kennedy discovered on the island of Tulagi with his head bashed in....

Returning to 1944 Italy to tackle two cases, including the murder of an accountant who may or may not have had military connections, U.S. Army Lieutenant Billy Boyle begins to suspect that his superiors do not want him to solve the murder.