Plot Summary Edit
Closer, Further (Part 1):
The opening chapter describes how Chester Rawls is the first to regain consciousness on a fungal shelf deep down in the Pore where he, Will Burrows, Elliott and Bartleby have crash landed. He pulls himself out and finds Will in a cave, moping over all the loss around him. Will then heads out onto the shelf to give Cal's body a burial of sorts. He and Chester carry the injured Elliott (who is unconcious and has a broken arm) with them as they set about exploring this alien and frightening world. The task of moving through the passages with the burden of Elliott and their equipment is made easier thanks to the reduced gravity at this depth in the Earth.
With the help of Bartleby’s tracking ability, they discover that there is someone else down there with them. While exploring tunnels, they are attacked by giant carnivorous creatures called spider-monkeys. They are saved by the intervention of Martha, a former renegade who was pushed down the Pore by her husband. She takes them to where she lives- a shack evidently built by the survivors of a galleon which was sucked down the another of the giant voids like the Pore. While there, she can tend to Elliott and protect the two boys. While at the shack, she talks about her dead son Nathaniel and what life down there is like.
The Old Styx, aware the Rebeccas might have died, sends Limiters to the Bunker to extract Dominion Virus from the corpses there. However, the plan is stopped by Drake, who uses a Coprolite mining machine to bulldoze and destroy the Bunker. Drake makes it back to the Colony, but finds the Styx Division is burning the Rookeries (the poor ghetto) and killing its residents. Drake makes it Topsoil, where he tries to get in contact with former members from his anti-Styx cell, but finds they have been killed.
Meanwhile, the Rebecca twins, who were pushed into the Pore by Sarah Jerome in her last dying act, are aware that Will is alive after seeing bottle rockets launched by him and Chester. They begin to plot against him with two Styx Limiters thrown in by the Old Styx. One of the Rebeccas and a Limiter approach Will's father, Dr Burrows, and attempt to bully him into finding them a way out of the Pore. Dr Burrows seems to have very little comprehension that the Styx are dangerous and capable of great cruelty and murder (he just wants to explore).
Martha's Shack (Part 2)
At Martha’s shack, Elliott’s condition deteriorates as she catches a voracious fever, and Martha warns Will and Chester that her son died after the same thing happened when he injured himself on an expedition two years previously. Much to Will’s surprise, the other Rebecca twin turns up alone the shack, and her life is only spared after Will stops Chester and Martha from killing her. The twin claims that she is innocent and has had to go along with her sister’s evil plans. Will appears to give her the benefit of the doubt, but Chester and Martha are highly skeptical. Will is further won over by the Rebecca twin as she gives him two phials, which purportedly contain the Dominion virus and its antidote.
Elliott’s condition worsens, and Will and Chester discover that Martha has been less than honest with them, and that there may be a source of modern medicines to help the girl. Although Martha is reluctant for them to risk the long journey, she eventually leads them to a “metal ship” which her son had stumbled across. Rebecca tags along, much to the annoyance of Chester. Along the journey, they discover creatures like Loop Snakes and rendevous at the Wolf Caves.
Meanwhile, the other Rebecca is still forcing Dr. Burrows to find a way out, becoming increasingly rude to him and denying him food. Behind the scenes, the Limiter is leaving markers for the other one with Rebecca to follow and find Will and Co.
The Metal Ship (Part 3)
When they get there, it turns out that the metal ship is actually a modern Russian nuclear submarine. Will theorizes it was sucked down by plate tectonics into the void and got stuck on a fungal-rock shelf. They are forced to shelter inside the sub while Elliott responds to the antibiotics. There is also the added risk that they may be attacked by Brights, giant mothlike flying creatures that are native to the void. The Rebecca with Will takes care of Elliott using her knowledge of medicine, while the group worries if they will run out of supplies.
As they finally set off from the submarine, the second Rebecca twin makes her appearance with Dr Burrows and the two Limiters. Will realizes the twin who surrendered to him has been lying all the time, as she orders Bartleby to attack him – the Hunter has been conditioned to follow her orders after being Darklit in the Colony. One of the Limiters is killed by a Bright, but the Rebeccas still have an edge. Just when it appears as if all is lost, Elliott recovers and says that she is half-Styx. She then primes a huge explosive in her rucksack, which is near the sub. In the subsequent explosion, Will and his father are separated from Chester, Elliott, Martha and Bartleby, while the Rebecca twins and the surviving Limiter seek refuge in the Russian submarine. The sub is knocked down the giant void it was in by the explosion.
The Underground Harbor (Part 4)
Separated from his friends and not knowing whether they are alive or not, Will is persuaded by his father to travel upwards. Will is somewhat disappointed that his father seems more interested in all they have discovered underground vs. the fact they are lost. After days of exploring they stumble upon the Underground Harbor, a deep-level fallout shelter from the Cold War. After Will has helped himself to various weapons from the armoury in the shelter, they manage to get an outboard engine to work, and attach it to a launch. Then they travel up a subterranean river linking the fallout shelter to the surface, and emerge in Norfolk, from where they make their way back to Highfield. Will also plans to get the phials given to him by Rebecca tested to see if they really contain the Dominion Virus.
Martha, Chester, Elliott, and Bartleby go back to the Wolf Caves. Elliott explains that her father was a Limiter and her mother was a Colonist. While there they eat wolf, and Eliiott and Chester catch up on what is happening.
Highfield, Again (Part 5)
Mrs Burrows, Will’s stepmother, has gone through a transformation after she manages to beat her TV addiction. She has returned to Highfield where she is kept under close surveillance by the Styx and their agents.
When Dr. Burrows and Will reach Highfield, they stop at the museum, which has been modernized since Dr. Burrows's disappearance. He gets into a debate with the new curator, then decides to visit Mrs. Tantrumi (the woman who found the light orb in Book 1). She ends up attacking Will's dad and is revealed to be a Styx agent. Luckily they are saved by Drake, who located them when he found that Will had called him on a phone in the Underground Harbor. They go to a safe house, where Drake explains the Styx to a cynical Dr. Burrows. He also helps Will overcome his Dark Light brainwashing from Book 1, which is making him have an urge to suicide jump. They are spotted by Styx snipers, and with the Styx knowing Will is Topsoil again, Drake takes him and Dr. Burrows to a house to rest. While there, Will's father decodes the tablets he found in the Pore (using Will's photos of the translating tablet), which seem to be some kind of map. Later on Drake has Dr. Burrows meet up with his wife at a roadside cafe. They get into an argument because Dr. Burrows wants to go back underground to explore, while Mrs. Burrows wants to escape somewhere safe with Will. In the end, Will is forced to return underground, as Drake's friend Leatherman's testing of the phials reveals they were Ultra Bug fakes.
Then there follows a parting of the ways as Mrs Burrows remains on the surface with Drake. He has asked Will to return back into the Earth and make sure that the risk of the Dominion virus has been neutralised. Will is accompanied by his father as they retrace the their route back down to the Underground Harbor. Eventually they get to where the submarine was blasted from the ledge in the void, which Will names Smoking Jean (after his aunt). He is reunited with Chester, Martha, and a fully recovered Elliott.
Departure (Part 6)
Drake, with help from a squad of former SAS soldiers and Leatherman, devises a plan to trap the Old Styx using Mrs Burrows as bait. The mission fails, as Mrs. Tantrumi detonates a Styx subaural bomb on the Highfield Common, knocking out everyone. Leatherman and the SAS soldiers are caught, and Mrs Burrows is captured and taken to the Colony where she is Darklit. However, it takes multiple Dark Lights to break her, much to the Second Officer's shock. Drake is saved by a mystery figure who drags him from his van before the Styx can get to him. Meanwhile, Dr Burrows, in a literal leap of faith, throws himself into Smoking Jean, followed by his son, and eventually by Elliott and Bartleby. Dr Burrows’ assumption that the gravity further down the void is progressively lower is proved to be correct. After locating the submarine, they search for any surviving Styx. Elliott then uses charges to destroy the sub. Dr. Burrows, driven by his conviction that there is a world at the center of the Earth, risks all their lives as he makes sure that they have no option but to continue towards it. They end up discovering the Crystal Belt, a zero-gravity belt at the Earth's center with massive triboluminescent crystals. They see a shaft of light and head towards it.
They finally make it through to the “Garden of the Second Sun” - a hidden world at the center of the Earth, complete with its own sun, mountains, oceans, and animals long since extinct on the surface. Assisted by Will, Dr Burrows begins to investigate one of three Mayan-type pyramids they find there. It seems as though they are finally safe from the Styx until Elliott spots some footprints. She, Will and Bartleby follow the trail and discover that the Rebecca twins and a Limiter have also made it through to the hidden world. They have camped at a pit head, which has a pool and metal hut.
After Elliott sets an ambush to deal with the Styx for once and for all, Will disobeys her and sneaks in to retrieve the Dominion phials. He is discovered by one of the Rebecca twins. Will shoots one of them while Elliott kills the Limiter. In the ensuing explosion Will makes off with the phials. Far from being angry at his disobedience, Will’s reward is a kiss on the cheek from Elliott.
Back on the surface, Drake has developed a drinking addiction after the failure of his mission. While in a bar he meets his savior- Elliott's Limiter father, who is a good Styx. He thanks Drake for saving his daughter, to which Drake says Elliott might have saved him. The Limiter then takes Drake home. In the Colony, Mrs. Burrows is looked after by the Second Officer and his family (much to the surpise of the Old Styx). Although in a coma state, Mrs. Burrows is still alive and recovering her senses slowly.
It seems as though Will’s prayers have been answered as he embarks upon his new life in this idyllic world, with Elliott as his companion and working with his father to discover incredible secrets from the past. Until one day Dr Burrows spots a WWII German bomber, a Stuka, in the sky.