Eddie Bosham (aka Charlie Boylan) is in prison on a murder charge. But he's not worried. He's innocent, and, anyway, he has hidden proof of a ghastly scandal that could bring down the monarchy.

Taking up his memoirs from where we left him, marooned on the Galapagos Islands, we find Eddie offering a young Charles Darwin an explanation of why the finches on the islands vary. In Texas, staunchly loyal to whichever side will win, he spies for General Santa Anna at the Alamo and, with the help of Emily Morgan, the ravishingly beautiful Yellow Rose of Texas, for Sam Houston at San Jacinto.

Eddie works the Mississippi riverboats as a cardsharp. Caught cheating, he is forced to jump ship and inadvertently stumbles across the secret that will launch the Californian Gold Rush. Finally, having traversed the girth of a nation, his disgraceful saga ends, back east, at a highly inflammatory revivalist meeting.