Suppose you had a gift so valuable that everyone wanted it, regardless of cost or consequence, even if the gift wasn't something that could be freely given.
Ben Richards (Christopher George, ex-The Rat Patrol) has Type O-Negative blood, but unlike most of us, Richards' blood makes him immune to disease, enabling him to seemingly live forever. Thus is the premise of The Immortal, which was spun from a 1969 TV-movie, which in turn adapted a novel by the same name.
In a way, The Immortal was formatted like a classic ABC series of the 60's, The Fugitive, in that Richards was forever on the run from the minions of an eccentric billionaire who wanted Richards' blood to preserve his own life, and keep Richards a prisoner.
The series' intro was narrated by voice-over legend Paul Frees (ex-The Millionaire), who was also cast in the movie. Unfortunately, Immortal lasted just 15 episodes and was cancelled in January 1971, only to return in the summer to fill time, which is when I believe I came across the show one night. I was only 8 at the time, so I didn't quite get the gist of the show, and wouldn't until more than 20 years later, when reruns aired on the then-Sci-Fi Channel (now SyFy).
Bart Broadhead uploaded the open:
Suffice to say, it was ahead of its time. I don't know if anyone in Hollywood, given all the recycling they're doing now, would approach this again.