When an eccentric millionaire presents at the Dublin Coroner's Office to report a found treasure, Benjamin Stirling sends him on to the National Museum. It is only when the man is found dead on his land on Tarrow Island and no treasure is mentioned when Stirling begins to get suspicious. Aged and recently widowed, Stirling makes inquiries but is stumped at every turn. He decides to take matters into his own hands and find out the truth once and for all. Heading down to the Atlantic West Coast of Ireland, he intends to find out what happened to Nicholas Spark and the vanishing Spanish Armada Gold he claimed to have unearthed Local police, councilmen and other officials are no help to him and Stirling must rely on his own wits and the local people for his answers. The more he finds out the more determined he is that Spark's death was no suicide. Something much more sinister is at work here.