Danno is taken hostage by a Vietnam veteran who is suffering delusional flashbacks and sees everyone as forces sent to kill him.

Big Chicken returns in a tense prison hostage drama when McGarrett has to give himself over to the criminals as a bargaining chip and use psychology to take control of the situation.

McGarrett is framed in an elaborate set up by Wo Fat, and has to contend with a foreign double amongst other problems.

Several faces from the past reappear as McGarrett must stop Wo Fat from carrying out his plan, a ninety second attack on a missile tracking base.