The Invincible Iron Man

Tony Stark, head of Stark Enterprises, was seriously wounded and captured in Vietnam while inspecting weapon prototypes in the field. To keep his injured heart alive, he built a revolutionary invention. It was a chest piece worked as an external pacemaker, but with further attachments, it became a mighty suit of power armor that allowed him to fight his way out. When he returned to America, Stark decides to use his armour to battle the forces of evil whenever they are present. And so, against communist spies like the Black Widow and technological mastermds like the Mandarin, Tony Stark secretly fights them posing as his own bodyguard, the Invincible Iron Man.