Is this self contained?

Meaning does the plot come solely from Part One of the book? I have just finished reading Part I of Atlas Shrugged and I am about to start reading the the second part. Quite interested in watching the movie despite the low rating. Would you recommend watching it already (considering it does not contain elements from part two - or three) or read the entire novel and then do it?

(Sorry if this is a repeated topic - didn't check much because I wanted to avoid spoillers!)

Cheers