Complex sentence: The plot centres on retrieving items from a Type XXI U-boat sunk of the Portuguese coast in the last days of World War II. Initially, the items are forged British and American currencies, for financing a revolution in Portugal, on the cheap.
Split into simpler sentences: The plot centres around retrieving items from a Type XXI U-boat sunk in the last days of World War II off the coast of Portugal. Initially the items are forged British and American currency, which will be used to help finance a revolution in Portugal on the cheap.