The plot is set onboard of a US nucler submarine USS Alabama. Two stalwarts of hollywood Gene Hackman and Denzel Washington worked in this movie. Its not a action thriller, but a tussle between the old and new generation. Captain Ramsey(Hackman) comes from the old school who believes in firm and strict action and Lt Commander Hunter(Denzel) comes from the new generation, who believes in last usage of nuclear action and have strong affinity for the men he commands.
The movie takes turns which results in mutiny and change of commands and strong denial of each others thought process. Rest you have to watch it yourself.