Before watching Atlas Shrugged Part II, I decided to watch the first film, and I watched them back to back. One thing to be noted is that the two films, although revolving around the same characters, have completely different casts, which felt very disjointed. The story is one overall all arch, and while they are two separate films, if you don't watch the first you miss a large chunk of the story. I believe that you could follow Part II without having seen its predecessor and still understand it, but I don't think it would have the same impact. Everything that happens in Part II is fueled by Part I:

Who is John Galt? That's the mystery that's woven throughout the films as the best and the brightest start disappearing, and is also used as a saying when one doesn't know an answer to something they are asked.

The main characters of the films are the protagonist Dagny Taggart, played by Samantha Mathis (Taylor Schilling in Part I) and her love interest Henry "Hank" Reardon, played by Jason Beghe (Grant Bowler in Part I). While there is a love story, it takes a backseat to all of the problems that they and the country are facing. The story starts in a dystopian United States (Part I starts in 2016, Part II does not specify) during an economic depression. Prices have skyrocketed and with the cost of fuel and oil rising, the predominant form of travel has become rail transportation, but even the railways are in need of repair.