I knew roughly what the plot was before I saw the movie, but my lack of knowledge was my best friend while viewing The Man in the Iron Mask.
King Louis XIV (Leonardo DiCaprio) is a young, selfish king that has imprisoned his younger twin brother, Phillipe (also Leonardo DiCaprio), in an iron mask for the past six years. D'Artagnon the fourth member of the three musketeers is his head of royal security. The people of Paris really despise the king, but inside the castle walls most are loyal to him. The three musketeers set out to free the twin and switch him with King Louis.
So that's pretty much the plot, bt it is so rich and full of twists and turns and oh it's good. John Malkovich is my favorite of the musketeers as Athos. He shows more emotion and his voice is so earnest...he is one of our most talented actors ever.
Leonardo DiCaprio shows extreme versatility in the dual roles. Both are obviously different and DiCaprio's entire demeanor changes when he's each role. He shows his acting prowess.
I highly recommend this film though the grade I'm going to give it may seem low, it's mostly because the movie is a tad long and could've used some editing. I give The Man in the Iron Mask a B+.