It seems the Black Knight is escorting a case that is sure to be Galleth's cane. To start the mission, you will need to take a picture of both the Black Knight and the case with your Binocucom. The first one is the Black Knight, which might require a high vantage point, then the second is of the case.
Once you take both pictures, you'll need to take out the two guards in the back. Use the Triangle and Square combo to take the farthest one out, which will attract the attention of the second one. With both gone, head up to the case and Bentley will have to play a hacking mini-game to unlock it (sidescrolling twin-stick shooter). The mission is over after you successfully hack the case.
