The Charlemagne Pursuit by Steve Berry

The provided excerpts, taken from "The Charlemagne Pursuit" by Steve Berry, present a complex thriller narrative centered around Cotton Malone's investigation into the disappearance of his submarine commander father, Forrest Malone, and the highly classified NR-1A sub in Antarctica years ago. The story involves a contemporary conspiracy orchestrated by Admiral Langford Ramsey, the head of naval intelligence, who is intent on hiding the truth about the sub's fate and eliminating anyone who knows about it, including former Navy personnel and Malone's allies, Stephanie Nelle and Edwin Davis. Malone's pursuit takes him across Europe, involving a German family, the Oberhausers, who possess ancient texts and maps connected to Charlemagne and a lost, advanced civilization known as the Holy Ones or Watchers, whose remains and knowledge were reportedly discovered during a 1938 German Antarctic expedition. Ultimately, the quest leads Malone to Antarctica, where he discovers a hidden underground city and the frozen, intact NR-1A submarine containing his father's body, while the conspiracy back in the United States involving Ramsey is exposed by the efforts of Davis and Nelle.