Daimio, Liz, Johann, Roger, and a host of B.P.R.D. soldiers battle hordes of frogs underground. Roger has become quite adept in battle, mimicking Daimio. When they find a nest, Liz burns it. Further underground, a figure from the Zinco Corporation collects the few tadpoles that escaped.[7]
At the Zinco Corporation, Mr. Pope, the head of the company, is pouring money into research and development to learn about the frogs. The frogs show a great deal of intelligence, and have learnt to talk and write.
Meanwhile, Abe has still not returned to the field since the Crab Point incident in Plague of Frogs. In British Columbia, Roger shows his skills as a leader by successfully avoiding a frog ambush.
Using the frogs he has raised and trained, Mr. Pope dons the outfit of a Nazi war criminal, The Black Flame, and goes out among the frogs in the wild.
In Montana, Liz is approached by an elderly woman who gives her a flower. Shortly afterwards, Liz passes out.[7]
Liz has a vision of a shadowy figure, warning her that the situation with the frogs is much worse than she can imagine. Liz awakens in a hospital bed, coughing up a balled-up piece of parchment. Professor O'Donnell sees the parchment which mentions Katha-Hem, a creature that will dwarf Sadu-Hem (the creature unleashed in Seed of Destruction and Plague of Frogs). Liz goes to speak to Daimio, interrupting some kind of therapy he's undertaking. After they both leave the room, unnoticed by Liz the "therapist" has mysteriously disappeared as if he was never there.
At the Zinco Corporation, Mr. Pope begins a ceremony that ignites true black flame on him.
In Ontario Roger is leading another attack against the frogs in a factory. After the battle, he sees The Black Flame watching him, then the factory explodes. All the B.P.R.D. soldiers are killed and among the ruins lies the remaining fragments of Roger's body.[7]
Liz is devastated by the news of Roger's death and moves into his room. Johann is alarmed by the manner in which Roger's remains are treated by the B.P.R.D.
Liz's visions of the shadowy figure continue, trying to shake her from her grief and into action.
In Lincoln, Nebraska, The Black Flame leads the frogs into battle. Abe finally decides to return to the field. The Black Flame learns that the frogs were only using him to summon Katha-Hem. In the battle that ensues, Abe is knocked unconscious.[7]
Abe awakens to find The Black Flame crouching over him, confessing to have made a mistake. The enormous creature, Katha-Hem, attacks the city of Lincoln. Realising the figure in her visions seems to know about Katha-Hem, Liz allows Johann to put her into a trance so that she can talk to him. This time Liz sees the figure clearly, a robed man covered in snakes. He shows her a tablet in hope that Liz will "see". Liz awakens from the trance in realisation. In Roger's room she finds the Shaman's device Roger recovered in Born Again.[7]
Johann, Abe, Liz and Daimio prepare themselves to attack Katha-Hem. Katha-Hem has been spewing masses of mist into Lincoln, transforming the city's population into monsters. When the B.P.R.D. attacks, Liz has a vision of a Hyperborean shaman holding the same device Roger found in Born Again. As the shaman chants, Liz copies his words, and the device becomes alive with energy. Liz releases the energy into Katha-Hem, destroying it.
The Black Flame, grateful to be free of the frogs, approaches Liz and asks her for help to get out of his suit, but he is taken by the frogs and dragged away.
In B.P.R.D. Headquarters, a crew begin dissecting Roger's body. When Johann learns of this, he is outraged and scares the scientists away. He then sits alone with the remains of his friend.[7]
