If you are a fan of it Indiana Jones For films, don't miss Father and Son, a well-hidden optional destination in Big circle'S Vatican City. You'll have to put in a bit of effort to do this, but you'll be rewarded with an exclusive adventure book, a few field notes, and a little callback to the third one Indiana Jones Film, The Last Crusade.
To even find “Father and Son,” you must complete the field research mission “A Nun in Trouble.” You start this automatically after your first meeting with Gina. The quest requires you to sneak into the Vatican City Museum via the Blackshirts campsite and then rescue Gina's friend Giuliana from the top of the Borgia Tower.
As part of your reward for completing “A Nun in Trouble,” you will receive Giuliana's Key, which also begins the “Father and Son” mystery mission. As Giuliana tells you, this will open a nearby door in Borgia Tower, as shown on your in-game map below.
At first glance it looks like it's just a shortcut, as the door leads to a balcony with a zip line that you can use to get back to the street. You land right in front of the Well of Confession, ready to continue the main story.
However, there is a second locked door near the zipline that holds the real secret. Open it with Giuliana's key to find a storage room where you will find a sleeping dog, a lazy cat, a locked safe, a bandage and stacks of disordered documents. One of these documents is a new adventure book that teaches the “Gas” skill, which allows you to perform stealthy takedowns from a distance using Indy's whip.
To solve this puzzle you need to get into the safe. First, open the drawer in the table in the middle of the room to find the Italian poem. The poem is irrelevant, but someone circled eight of its letters: I, R, I, A, T, A, S, O.
Second, open the drawer under the nearby typewriter to find a second document, the Polybius Square Diagram. This provides a cipher for the letters of the Italian poem, albeit one not commonly used in video games.
In practice, The biggest stumbling block in “Father and Son” lies in the poem’s italics. It's easy to confuse the final “O” with an “A”, which messes up the entire code.
As you move through the diagram, the circled letters become a 4-digit code:
I + R = 5
I + A = 8
T + A = 7
S + O = 3
The code for the safe is 5873.
Open it to find the Siwa photo, junior report, office photo and senior report. This will give you 60 Adventure Points for finding all 4 notes and another 100 for completing Father and Son.
Indiana Jones and the Great Circle is now available for Xbox Series X/S, Xbox Game Pass and PC via Steam.
