Eph watched the throbbing, which he found to be irregular, not like a true heartbeat at all. He saw something moving around inside it. Wriggling.

“A…worm?” said Nora.

Thin and pale, lip-colored, two or three inches in length. They watched it make its rounds inside the heart, like a lone sentry dutifully patrolling a long-abandoned base.

“A blood worm,” said Setrakian. “A capillary parasite that reproduces in the infected. I suspect, though have no proof, that it is the conduit of the virus. The actual vector.”

Eph shook his head in disbelief. “What about this…this sucker?”

“The virus mimics the host’s form, though it reinvents its vital systems in order to best sustain itself. In other words, it colonizes and adapts the host for its survival. The host being, in this case, a severed organ floating in a jar, the virus has found a way to evolve its own mechanism for receiving nourishment.”

Nora said, “Nourishment?”

“The worm lives on blood. Human blood.”

“Blood?” Eph squinted at the possessed heart. “From whom?”

Setrakian pulled his left hand out of his pocket. The wrinkled tips of his fingers showed at the end of the glove. The pad of his middle finger was scarred and smooth.

“A few drops every few days is enough. It will be hungry. I’ve been away.”

He went to the bench and lifted the lid off the jar—Eph stepping back to watch—and, with the point of a little penknife from his keychain, pricked the tip of his finger over the jar. He did not flinch, the act so routine that it no longer hurt him.

His blood dripped into the serum.

The sucker fed on the red drops with lips like that of a hungry fish.

When he was done, the old man dabbed a bit of liquid bandage on his finger from a small bottle on the bench, returning the lid to the jar.

Eph watched the feeder turn red. The worm inside the organ moved more fluidly and with increased strength. “And you say you’ve kept this thing going in here for…?”

“Since the spring of 1971. I don’t take many vacations…” He smiled at his little joke, looking at his pricked finger, rubbing the dried tip. “She was a revenant, one who was infected. Who had been turned. The Ancients, who wish to remain hidden, will kill immediately after feeding, in order to prevent any spread of their virus. One got away somehow, returned home to claim its family and friends and neighbors, burrowing into their small village. This widow’s heart had not been turned four hours before I found her.”

“Four hours? How did you know?”

“I saw the mark. The mark of the strigoi.”

Eph said, “Strigoi?”

“Old World term for vampire.”

“And the mark?”

“The point of penetration. A thin breach across the front of the throat, which I am guessing you have seen by now.”