A French nuclear sub is on a mission to nuke Iran based on flawed intelligence. Another French sub is sent to stop that Sub based on the proper intelligence that a Possible missile attack is by Iran when in fact the rumor was initiated by an isis type group. The attack sub is sunk by another French sub to prevent a global attack with a lot of tense action involving an acoustic sub engineer that locates the attack sub with sonar. One wonders why the French were going it alone in nuclear warfare.