In 1938, an intrepid archaeologist finds himself on a perilous quest to track down his father, who has vanished while searching for the Holy Grail, a legendary artifact that is said to grant eternal life. The protagonist receives his father's Grail diary by mail and deciphers a clue that leads him to Venice, Italy. In Venice, he enlists the help of a beautiful and scholarly Austrian woman. They discover an ancient tomb that houses the remains of a knight templar, which provides another vital clue to the Grail's whereabouts.

However, they are not alone in their hunt. The archaeologist learns that a sinister Nazi group is also searching for the Grail, using his father's research to aid their quest for world domination. The Nazis are close on their heels as they travel from the catacombs of Venice to the heart of Nazi Germany. The duo must stay one step ahead of their enemies while solving the mysteries of the Grail's location. The journey to find the Grail and rescue his father takes the protagonist on an adventure through different countries, testing his knowledge and courage, and revealing the depth of his relationship with his estranged father.