It's a great story of how Kirk TRULY becomes the captain of the Enterprise, and what he learns about himself along the way.
The first film was about Kirk becoming the captain of the Enterprise.
The second film was about Kirk TRULY becoming the captain of the Enterprise.
The third film will be about Kirk REALLY TRULY HONESTLY THIS TIME becoming the captain of the Enterprise, while searching for Whales and fighting off a sexy Borg Queen, while Q gives him a baby Picard to look after and teach him the true meaning of Christmas. Or something.