El Estanque de Fuego es la tercera y última parte de la llamada Trilogía de los Trípodes, comenzada en Las Montañas Blancas y continuada en la Ciudad de Oro y Plomo. En esta novela, Will Parker es escogido en primer lugar como señuelo para detener un Trípode y capturar a uno de los Amos; después, como miembro de una de las tres expediciones destinadas a destruir, desde su interior, las Ciudades de los Amos. Finalmente, en el desesperado y crucial ataque a la última Ciudad, cuando el futuro del mundo pende de un hilo, Will jugará un papel vital.

Will and Fritz travel to Eastern Europe, the Caucasus, and the Middle East to organize resistance against the Tripods. The resistance, having ambushed a Tripod and captured a Master, discover that alcohol has a strong soporific effect on them, and use this knowledge to simultaneously attack their cities. Having introduced alcohol into the aliens' city water systems, two raiding groups kill the Masters by forcing open airlocks and exposing the unconscious aliens to Earth's atmosphere; but the attack on the last city (located in Central America) fails. A secondary plan is undertaken using hot air balloons and newly developed bombs. The attack is initially unsuccessful as the timers on the bombs cause them to detonate either before making contact with the dome of the city, or after the bomb has fallen clear. Henry jumps from his balloon onto the city's domed roof and holds the bomb in place, sacrificing himself but shattering the dome. Earth's atmosphere kills the Masters, and Henry is remembered as a hero.

Several years later, the Masters' atmosphere-seeding spaceship arrives and destroys the remains of their cities, then leaves – presumably since the cities contained "star maps" which showed the location of the Masters' home world, also to prevent the humans from reverse engineering their technology – although Beanpole notes that they have already learned much from the cities. Modern human technology, which was halted during the Masters' rule is rediscovered rapidly, including the theory of space travel.

The saga ends with the Resistance leader Julius being deposed. As a result, the alliance built during the resistance falls apart, with nationalistic hostilities appearing, each country going their separate ways in contrast to Julius' efforts to unite the world. Will, Beanpole, and Fritz reunite as a tribute to Julius, to work towards establishing a better world.

“El Estanque de Fuego” es la tercera y última parte de la llamada "Trilogía de los Trípodes", comenzada en “Las Montañas Blancas” y continuada en “La Ciudad de Oro y de Plomo”. En esta novela, Will Parker es escogido en primer lugar como señuelo para detener a un trípode y capturar a uno de los Amos; después, como miembro de una de las tres expediciones destinadas a destruir, desde su interior, las Ciudades de los Amos. Finalmente, en el desesperado y crucial ataque a la última Ciudad, cuando el futuro del mundo pende de un hilo, Will jugará un papel vital. Los seguidores de la "Trilogía" comprobarán cuánto tiene que ver este libro con la historia real, pues se verán implicados de modo insospechado en la aventura de sus personajes, y en su apasionante lucha por la libertad. ( )