It is 1938 and adventurer Indiana Jones is joined by his father on this quest, preventing Adolf Hitler from capturing the Holy Grail. He will have to deal with Nazi guards, the Luftwaffe and enemy spies as he tries to stop the tyrannical Nazi leader.
The Graphic Adventure uses the same SCUMM gameplay system as the previous Maniac Mansion. Most of the screen is used for a visual rendition of the current scene. At the bottom of the screen are words, which can be clicked on using the mouse to activate their functions. For example, objects can be picked up, used, pushed or pulled, and turned on and off. Most locations are from the movie, but some further scenes are added.
In keeping with Indiana's action-man persona, the game also features pure action scenes. Unlike most Lucasfilm adventures, you can die.