wounds causes the bacteria to switch from being anaerobic symbionts to aerobic parasites, rapidly consuming their hosts when exposed to air and thus giving them the appearance of instantly liquefying. However, he discovers the bacteria also produce resilient "body glue" that instantaneously seals blunt or narrow wounds, explaining how the vampires are bulletproof. Lastly, he deduces now that there are in fact two differently-reacting types of vampires: conscious ones who are living with a worsening infection and undead ones who have died but been partly reanimated by the bacteria. After three years, Neville suddenly sees a terrified woman named Ruth in broad daylight. The two cautiously gain each other's trust and even share a romantic embrace. Neville explains some of his findings, including his theory that he developed immunity against the infection after being bitten by an infected vampire bat years ago. He prepares to test Ruth to determine if she is infected or immune, vowing to treat her if she is infected, but she knocks him unconscious. When Neville wakes, he discovers a note from her confessing that she is indeed a vampire herself. Her note suggests that only the undead vampires are pathologically violent but not those, like her, who were alive at the time of infection and who still survive due to chance mutations. These living-infected have slowly overcome their disease and are gradually developing a new society and new medications. Ruth admits she was sent to spy on him by her comrades and that he was responsible for the deaths of many of her fellow vampires, including her husband. Still, Ruth reiterates her romantic feelings for Neville and urges him to flee the city to avoid capture. Neville ignores Ruth's warning, assuming he will be treated fairly by the new society of living-infected. However, his mind is changed when he watches a group of them annihilate the undead vampires outside his home with fiendish glee. In a panic, Neville opens fire on them but is in turn shot and subdued. Imprisoned and dying, he is visited by Ruth, who informs him that she is a senior member of the new society but, unlike the others who perceive him as a murderer, she does not resent him. She acknowledges the public need for Neville's execution but, out of mercy, gives him a packet of fast-acting suicide pills. Neville accepts his fate and asks Ruth not to let