The tag-line, "After zombies take over the Earth, vampires must protect the last surviving humans so they can live off their blood," summarizes the set-up for the four issue series. The first series was completed in December 2007.
Crosby has plans on filming the story as a movie himself, and considers the comic more of a storyboard.
In early 2008, a second series of Last Blood began being posted.
A month later, Murdo and Grady carry a dead zombie to a dumpster. Seeing that his dog tags and uniform belonged to WWII, they ponder on the possibility of it being The First Zombie. Mac rises in the morning and goes out to golf a little, where he is approached by April Davis, a school teacher. They discuss Mac making a supply-run to the nearby zombie-infested city that day, and he leaves, armed only with an axe.
Then, a group of approximately fifty zombies approaches the school and Murdo and Grady attempt fending them off and called the rest to help in the effort, but the other survivors cowered and didn't come to their help. As they ran out of ammunition, they desperately defended themselves with a shovel and a pipe. Suddenly two strangers appear to join them in the battle, quickly killing all the zombies with guns and swords.
After stopping the zombies, they meet with the survivors and introduce themselves as Matheson and Valerie, explaining that they are vampires that require their blood to live. April shoots Matheson out of shock and runs outside to be sick. Math follows her and explains that they are there to help, since the survival of vampires depends on the survival of humans and that it would be like donating blood to the hospital since they can live off very little blood. He reveals that she is the key to human survival, since she has been responsible for keeping everyone calm and normal by continuing to teach classes.
As it begins to rain, he convinces her to go back inside and start class 8 o'clock as usual. That day at lunch, Math tells April that The First Zombie was a vampire who had been starved of blood for 65 years, his sanity breaking down in pain and body decomposing as he turned into this new form. He also reveals that a vampire named Addison Payne has been largely responsible for many of humanity's finest medical advances over the past few centuries, and has been working on a 'cure' for the zombies. The First Zombie, the zombie shot in the head by Murdo at the beginning of the issue, is seen hiding in the bushes listening in at the end of the issue.
Devian, a vampire descended from the first vampire with the consequent ability to fly, arrives to tell Math that the last remaining humans in Canada have been killed. Math smells lots of zombies surrounding Mac and asks Devian to go rescue him before heading to Mexico to help protect the survivors there. Devian doesn't make promises since she is blessed with flight and not strength.
Math meets with principal Howard and explains some false myths about vampires, revealing that they aren't related to the Devil, they can walk in sunlight, they reflect on a mirror.
As zombies are about to kill Mac, he accidentally shoots Devian and she rescues him by shooting the zombies and opening a way to escape. April tells Math that the day the outbreak started, a tornado destroyed the communication lines and because of that the children don't know about the zombies. That night, Valerie unsuccessfully attempts to seduce Math. He later tells Murdo, who finds Val attractive, that his best chance is right now. Jimmy, one of the children, asks for a gun because he suspects that there are zombies after seeing the bodies in the dumpster. Murdo refuses, but Grady gives him one that evening in secret explaining him that the zombies are real. Murdo and Val sleep together while Math drifts off to sleep in the presence of April. That night zombies attack the school through an underground passageway. Jimmy makes a brave defense but is turned into a zombie and bites his mother, Murdo's sister while Murdo's mother dies of a heart-attack.
Math kills Jimmy and his mother. Murdo mourns for his mother, and is approached by Math who tells him that both he and Val will need to feed off his mother, since her blood is untainted. The principal confesses that he is to blame for Jimmy's death, since he shouted his name when zombies were about to kill him and Jimmy bravely rescued him, but when escaping he hit a zombie and his knuckles were scraped by the zombie's teeth. They amputate his arm hoping to stop the spread of the infection.
April tells Math about her grandfather, Sullivan Davis, and he begins to suspect that he is The First Zombie. Murdo blocks the tunnel with a secret buried switch, revealing that the tunnel is named after Sullivan, and that its existence is a secret only known by the town's people that served in the army.
Devian and Mac sit in a tree, and she tells him about a similar outbreak that happened in the 12th century. She explains that the zombies are controlled by a so-called schaemiac. The zombies beneath them begin heading toward the school all of the sudden and Devian leaves to find Addison Payne.
Murdo buries his mother, his sister, and his nephew, Jimmy. Val expresses her sorrow and asks if there's anything she can do and Murdo asks her to turn him into a vampire so he can be strong enough to protect the survivors. Math goes after Mac, whom wants to get his truck with supplies before returning.
The entire zombie army approaches the school, but before the battle has even begun, Addison Payne crashes his plane into the first ranks of the zombies, a few thousand. The rest of the vampires come out of the wreckage, back from unsuccessfully defending the humans in Mexico. Addison Payne reveals that this group are the only remaining humans on Earth.
Murdo is turned into a vampire by Val, and Val forces him to drink a pint of his mother's blood to end his first hunger. Murdo finds Grady with the Principal, and tells Grady to watch him since his blood is tainted and will turn soon. Then he changes his mind and decapitates the principal, before jumping off the roof to join Rage, who is having fun killing zombies with his bare hands. Addison Payne and the rest discuss tactics and make note of The First Zombie's plan to chain the vampires, torturing them with the hunger pains for 65 years till they too become schaemiacs. Math notes that a small group of 3000 zombies is approaching fast from the west, which suggests that The First Zombie is leading them, so he leaves with two other vampires to find him, but his car is destroyed by The First Zombie with a rocket launcher. The zombie army charges, forcing him and the others to go back to the battle.
After hours of fighting the pile of dead zombies is taller than the school (The First Zombie's plan is to wear the vampires out). They are eventually chained by armored zombies and led into the school. Val breaks free and cuts Murdo loose as well before being staked by The First Zombie. Murdo is chained again, The First Zombie orders his minions to kill the humans but he stops after April yells at him, thinking that he is her grandfather.
He reveals that he isn't Sullivan Davis, he is Francis Murdo Senior, the grandfather of Murdo. Seeing Addison Payne as a threat to his plans, The First Zombie stakes Payne and kills him. He then comments to April that she smells like her grandmother, the woman he loved. He approaches her, saying that he would allow her and the children to live. April thanks him and hugs him, using the opportunity to kill him with a concealed stake.
Immediately after The First Zombie is dead, his zombie army is unbound and chases the humans. The vampires take the humans and jump out the windows. Devian follows Payne's instructions: to take the youngest boy and girl away. The children's squirming, however, forces her to drop the girl, who is saved by Sullivan Davis who has become a schaemiac. Sullivan has 3,000 armed zombies with him. The reinforcements help the vmapires and humans win the day. It is revealed the note that Payne gave to Devian, presumably containing instructions for repopulating the human race, really said "Thank Sullivan for me."
Hours later April and Math sit at the edge of the pond, taking a count of the surviving humans, which amount to 23. They discuss the repopulation issue. After April asks whether it is possible for humans and vampires to conceive, Math comments cryptically that the child "wouldn't be human." He then retrieves the briefcase Addison carried with him. Inside it is the cure for vampires, an unknown mixture contained in otherwise ordinary-looking vodka bottles. Drinking a mouthful will make a vampire human again, provided that they were not born a vampire. Math tests the cure, and it works, making him the 24th human. The story of Last Blood ends there.
A sequel has already been announced, and appeared online towards the end of December.
It is also available in full as an online archive as free PDFs from Wowio.