The Delphi project was the result of the research of an imaginative doctor who always believed in the truth behind folklore. Dr. Samuel Hirsch's research came to the attention of the government at a time of deep paranoia in the military. They see applications to the theories in Hirsch's research that could create a nearly immortal soldier. They fund the mission and support it with all manner of personnel and equipment. Hirsch pays no heed to the ramifications of accepting such help. He is after his personal holy grail, a real vampire. He is thrilled to find that such a being is real, but his excitement makes him reckless. He gets too close to the vampire who was wounded during the capture, and he is killed by the being.
The project continues with a new doctor. the staff believes it is to honor Dr. Hirsch's sacrifice. The military has other ideas. The new doctor, Joesph McKay, was picked from the VA Hospital staff, because he was handy and had financial problems that could make him cooperative. Joe Mckay immediately treats the vampire, Simon Molinar, as a patient. In fact, it seems that the men bond fairly quickly. The staff notes that Mckay is prone to do small kindnesses for Molinar. And though the pair are often in heated arguments about Molinar's nonchalant view of human life, Mckay is often protective of the vampire. He and the project director, Dr. William Bassett are almost always at odds over how Molinar is being treated. These disputes grow more heated as the experiments progress. Hirsch's theories prove correct. The condition known as vampirism is caused by a virus in Simon's blood. Only those with a certain genetic marker can be affected by the virus and thus be transformed into a mutant like Molinar. Joe McKay has the marker. Those behind the experiment want the Doctor exposed to the virus to see if he transforms. He is far more attractive a research subject as he has not murdered anyone. Simon will be destroyed if McKay can be transformed. Of course, no one reckoned on how the vampire would react to this notion. He takes the opportunity to escape during an attempted take over by a crazed lab researcher bent on destroying the project. The escape is violent and bloody leaving the survivors severely traumatized.
In the aftermath, Joe McKay is relocated to Washington, DC to work at Walter Reed as a reward for cooperating in the investigations. For him, life is actually better than ever before. He is respected. His work is satisfying. Most of all, he has found love. Then, in one night, all that success and happiness turns to dust. Molinar comes to take him away. And, in the process, the vampire exposes that his entire life in DC was a lie. Delphi was reborn, and McKay was to be the star subject along with many unsuspecting soldiers who had the marker.There is nothing either of them can do about the other subjects. The new Delphi was well protected in a heavily guarded quasi military facility. So they run to avoid capture and work on culling together enough evidence from the first form of Delphi that is scattered in research centers at universities all over the country. If they find enough concrete evidence, they can expose the whole project to the press and get it shut down.
Thus, these very different beings have to live together and trust each other for protection. Along with avoiding those who hunt them, they have to figure out the other strange phenomena they run across in their quest. After all, Simon always said, if he exists, other strange beings may also. Joe is just hoping to stay alive long enough to figure out how to stay safe. He also has to figure out how to keep Simon from giving him his 'gift' so that they can be companions forever.