The tale begins in Manhattan, where cockroaches are spreading a deadly “Strickler’s disease,” claiming hundreds of the city’s children.
Due to inability to develop a cure or vaccine for the disease, Dr. Peter Mann, deputy director of the CDC, decides to recruit entomologist Dr. Susan Tyler.
Dr. Tyler uses genetic engineering to create what she calls the “Judas breed,” a hybrid of a mantis and a termite that releases enzyme which accelerates the roaches’ metabolism. As a result, the roaches burn calories faster than they can nourish, thus starving to death.
The roaches carrying the disease are successfully eradicated, and Peter and Susan later get married.
Three years later, a priest is chased and dragged underground by strange assailant. The only witness is Chuy, an autistic boy with habit of imitating noises, who refers to the attacker as “Mr. Funny Shoes,” to his disbelieving guardian, an immigrant subway shoe shiner named Manny.
Later two kids sell a “weird bug” from the subway to Susan. Upon testing, she realizes that it is similar to the Judas breed. Initially, she refuses to believe since the specimens she had released were all female. They were designed with a lifespan of a few months, which should have ensured that the breed would die off after a single generation. However, before she can examine the insect any further, it is stolen by a strange figure who escapes out the window.
After informing the police, she consults with her mentor, Dr. Gates, who autopsies a larger specimen found in the city’s sewage treatment plants. He finds out that its organs are fully formed, meaning the Judas breed is not only alive but has developed into a viable species, manifest by a sizable colony underneath the city.