The book was released in November 5, 2019.
One week after their eleventh birthday, the Fowl twins--scientist Myles, and Beckett, the force of nature--are left in the care of house security (NANNI) for a single night. In that time they befriend a troll who has clawed his way through the earth's crust to the surface. Unfortunately for the troll, he is being chased by a nefarious nobleman and an interrogating nun, who both need the magical creature for their own gain, as well as a fairy-in-training who has been assigned to protect him. The boys and their new troll best friend escape and go on the run. Along the way they get shot at, kidnapped, buried, arrested, threatened, killed (temporarily), and discover that the strongest bond in the world is not the one forged by covalent electrons in adjacent atoms, but the one that exists between a pair of twins.
The book begins with the antagonist, Lord Teddy Bleedham-Drye, the Duke of Scilly Isles. It is said that he had dedicated his one hundred fifty plus years on Earth in order to stay in it as long as possible. In those years, he had done extreme anti-aging practices, such as ingesting tons of willow-bark extract and slurping gallons of therapeutic arsenic. Though there had been side effects, such as getting elongated forearms. However, he was frustrated that, even though he had extended his life, he reasoned that he had yet to "hit a jackpot", and so, set out on a quest to find a "fountain of youth" to live for eternity.
He then went ahead to interview the oldest people on Earth, which took over the course of five years. He found them all to be useless, until he located an Irish monk called Brother Colman, working in an elephant sanctuary in California. Lord Teddy went ahead and slipped a dose of truth serum in the monk's tea, in which Brother Colman told a story of the how the holy well on Dalkey Island had come to its healing waters in the fifteenth century.
Teddy did not believe a word of what he said, but had thought that the word Dalkey sounded an alarm bell somewhere on his mind. He eventually performed a couple of verification checks. Firstly, he had unbuttoned the monk's shirt and saw that his chest was marked with ugly scars, which was consistent with the story the monk was telling. Finally, he snipped off the monk's left pinky finger with his pruning shears and sent it into a laboratory called Advanced Accelerator Mass Spectrometer Laboratory, which specialized in radiocarbon dating.
After several weeks, Teddy was back in England, lounging in his bath of electric eels on the island of St. George in Scilly Isles. When he came upon the envelope from the laboratory, he had expected that it was to be useless. However, the results had made him sit up quickly, as the results stated that Brother Colman's pinky finger was in the four hundred to five hundred year old age range.
He then quickly dressed himself in a hunter outfit and set out to Dalkey Island. Halfway across the Irish Sea, he had realized that the word "Dalkey" sounded familiar was because Artemis Fowl I had hung his hat there, which he exclaimed that he was a force to be reckoned with. Nevertheless, his determination never wavered and told that he must have a troll's venom, which was actually the "fountain of youth" he was talking about.
Then our perspective shift into Myles and Beckett Fowl. A week after their eleventh birthday, they were walking along a stony beach of Dalkey Island, in which the Fowl family had recently moved into Villa Eco. It was a newly built environmental friendly house, as opposed to the Fowl Manor. The twins' parents were away but they were being guarded by the house itself, which had NANNI, an intelligence system to keep an electronic eye on them.
When Myles was finished in collecting seaweed for his homemade hair gel, he turned to Beckett for bedtime, as he said that they require 10 hours of sleep for proper development in their bodies. However, Beckett was too busy talking in seal language and so, Myles sighed as they would once again fail to get on bedtime. He then tapped the right arm of his spectacles and told NANNI to send a drobot to carry Beckett. NANNI then insisted in a female voice that both of the twins instinctively trusted for some reason, and told him that there was no flying Beckett home unless it was for emergencies only.
Myles then called to Beckett once again that he will tell him a short story before bed if he agreed to come home. Beckett then asks on what story will it be and Myles suggested that it will about the discovery of Schwarzschild radius, which lead to the identification of black holes. Beckett was unimpressed and then told him to tell the adventures of Gloop (his beloved fish) and Angry Hamster (sculpture he made from chewing an IQ test) in the Dimension of Fire instead. Myles eventually agrees, as when he himself was unimpressed and because of that, Beckett refused to come home. Beckett then gets happy and asks him for a wrist bump, in which they did. Myles then tells him to bid farewell to his dolphin friend before they went. Beckett then turned, only to find that a troll had surged upward through the shale on the water's edge and had collapsed on the beach.
A sneak peek of the first chapter was released with the new 2018 printing of the existing Artemis Fowl novels. The sneak peek was released online on Artemis Fowl Confidential during an official international cover reveal on the 2nd May 2019.