It's not so much a Rocky-type story as it is a documentary of sorts. You're with Cal as he prepares to do the only thing he knows how to do (fight) and slowly shuts down all other aspects of his life as the big day approaches. He's grappling with himself through the whole story in a search for purpose, a need to understand himself and why he puts his body through this torture. His manager Riley is a father figure to him, a man who wants nothing but the best for Cal, but who also has to deal with the fact that Cal's destruction is part of the job. He doesn't want to see Cal hurt, but he can't tell him to scrap the fight, either.
The build-up to the big night is slow, focusing on a lot of the mundane details that come with travel, training, sparring, and mental preparation. The fight itself, like any good MMA brawl, is short and shocking, and the ending leaves you to ponder what has been won and lost.