Prisoner

Nathan K is an immortal who can sustain himself by holding two souls, making him nearly impossible to kill as long as his second soul is preserved. After a year in England, he's eager for action and to reunite with Robin, but his plans lead him into a dangerous world when he helps free an imprisoned immortal, uncovering surprises involving powerful figures like the Cardinal. As he navigates these perilous events, Nathan faces challenges that reveal the world of immortals is far more complex than it appears.