Grey Gold is set against the backdrop of Civil War San Francisco and an attempt by Confederate agents to steal California gold. Every other week during those years, several million dollars in bullion and minted coins were loaded on steamers in San Francisco and shipped through Panama to New York. The plotters had a letter of marque from the Confederate government, to pillage Union shipping for a share of the seizures. This was an accepted, but declining way for nations to make war on one another. American naval hero John Paul Jones was a privateer. Some of the founding fathers were privateers. Out-of-work privateers in the 17th and 18th Centuries became pirates.
Kentuckian Asbery Harpending secured a letter of marque from Jefferson Davis with the names of the captain and the ship left blank. Harpending was a colorful character even if half his stories are to be believed. I read his biography and have questions about his adventures. He was a filibuster, sort of a land pirate, a veteran of the Battle of Shiloh, and fabulously wealthy, by about age twenty. He partnered with Ridgely Greathouse a paroled Confederate soldier whose family had businesses in California. (Instead of going to prison camps, captured soldiers could give their paroles and agree not to fight until they were exchanged. That's another story.)
Greathouse and Harpending bought a ship in San Francisco, the Chapman, and recruited Southerners and other adventurers to the scheme. San Francisco and California were Union, but there were plenty of Secessionists ready to take the state for slavery. A member of the crew snitched them off and the plot was busted. Four men stood trial for treason and piracy and were sentenced to ten years in prison. A few months later, Abraham Lincoln pardoned them. Greathouse was not out of the woods, though. He had violated the terms of his parole so the army picked him up and shipped him to New York for court martial. He murdered a guard, escaped, and fled to Canada until after the war.
Some of the gang tried to organize a ship in Victoria in British Canada, but Union agents broke up that plan. There were pro-Confederate gangs in California that robbed and murdered in the name of secession. One of the Chapman crewmen, cut loose after the arrests, was hanged for killing a sheriff.
Harpending went on to be rich in real estate and mining. New Montgomery Street in San Francisco where the Palace Hotel is was developed by him. Greathouse died in an epidemic in the 1860s.
I had fun transporting a character from Taste of Freedom to California and getting him sucked into a murder and this plot.