The Czar’s Last Soldier

In 1974 at a Nebraska post office, Sam Gibbons and Roscoe Barnes are removing the old post office boxes and replacing them with new ones. Both men are WW2 veterans who teamed up as general contractors. When the old post office boxes are removed, a letter hidden between warped boards falls to the floor. The letter, dated 1942, is from a marine who died on Corregidor and gives the particulars of a jewel theft he committed at the Shanghai Officer's Club in 1941.
Not wanting the Japanese to glom onto the jewels after Corregidor surrendered the marine buried them. Sam and Roscoe find the jewels then place a 42.5 carat diamond broach up for auction. The broach is identified as the Star of Golconda, the property of a czarist officer, and the FBI is called in. Claims from half a dozen countries are received and Sam and Roscoe are thrust into an international legal battle.