Like many ABC television shows of the late 60s and 70s, "The Immortal" began its like as an installment of "The ABC Movie of the Week". Often the network would show pilot movies and if they did well, they'd green light the series. Or, they'd do this to introduce the series. This was the case with shows such as "Kolchak: The Night Stalker" as well as "The Six Million Dollar Man"...and "The Immortal"...which was a short-lived series starring Christopher George.
When the film begins, a very rich but sick old man (Barry Sullivan) is in a plane crash. When he receives a blood transfusion, however, he recovers remarkably quickly...too quickly. The doctor on the case (Ralph Bellamy) investigates and the trail leads to Ben Richards (George). It seems that he has unusually powerful blood and he's immune to all illnesses and he also should expect an amazingly long lifespan! However, the rich old man is NOT a nice guy--and when he learns about Ben's special gift, he decides to kidnap him and hold him prisoner so that he can keep receiving this 'gift'. After all, the benefits of the transfusion are short-lived and the old guy realizes that he can also live for a very, very, very long time if he keeps Ben alive and keeps draining him periodically. He also might be willing to let other rich and powerful men have Ben's blood! Not surprisingly, Ben eventually escapes and then spends the rest of the film on the run...with the millionaire's goons always in pursuit.
This is a really neat idea and it left me wanting to see the TV series. Unfortunately, I don't know of any way to see it and only the pilot is available now on YouTube. Too bad...the premise is great...and a bit like "The Fugitive".