A group of terrorists-at-sea demand a $25m ransom when they threaten to blow up an oil rig if their demands aren't met by the set deadline.

Good guys to the rescue led by an eccentric Roger Moore, who once said in an interview that he preferred this film to all the James Bond movies he had starred in. He also claimed he was mis-cast in the role. Very good entertainment.
Based on the book Esther, Ruth and Jennifer by Jack Davies, who also wrote the screenplay for the movie.