The Diamond Of Darkhold

The Diamond of Darkhold (2008) is a middle grade dystopian novel by Jeanne DuPrau that concludes The City of Ember series. In this installment, protagonists Lina Mayfleet and Doon Harrow embark on a quest to find a mysterious invention left for the people of Ember by the city’s Builders. With themes of The Legacy and Impact of Ancient Technologies, The Importance of Cooperation in Problem Solving, and Self-Sufficiency Through Knowledge of the Natural World, The Diamond of Darkhold explores the impact of hope, open-mindedness, learning, and discovery on conflict and struggle. 

This guide uses the 2008 edition by Random House Children’s Books.

Content Warning: The source material and guide feature depictions of illness, death, and animal death. In particular, the text mentions global war, plague, disaster, and worldwide apocalyptic destruction.

Plot Summary

Just before a cataclysmic war they believe is near, the Builders construct and stock an underground city called Ember for a group of people to use for survival. As directed by the chief builder, the Builders leave a recent invention from their time (the mid-21st century) in a steel-lined vault meant for the future people of Ember that will help them when they emerge. The chief builder notes that an instructional manual (the Directions for Use) should accompany the invention; he also plans to set a timed lock on the vault to open once it is safe to re-inhabit the surface.

Hundreds of years later, 13-year-old Doon Harrow helps sort scavenged lumber and building supplies near the old Pioneer Hotel outside the village of Sparks. He works alongside his father, Loris, and other laborers. The day is cold and wet, and the growing dark and approaching storm make conditions difficult and dangerous.

Doon reflects how winter in Sparks has led to many worries, like hunger and sickness. He knows one reason Sparks is struggling is the lack of electricity. Over 240 years before, the modern technological world ended in a great Disaster. Only scattered groups remained on Earth to piece life back together—and one group under its surface in the cavern city of Ember, created by the Builders 50 years before the Disaster struck. Generations later, Doon, his father, and about 400 other Emberites found Sparks after Doon and his friend Lina Mayfleet led them from their underground home. Some parts of life on the surface are fascinating to Doon, like animals and weather. However, food supplies are low, candles must be used cautiously, and the lack of electricity causes hardship.

Doon’s father falls and cuts his hand on glass windows. Doon takes him to Doctor Hesper’s house, where Lina lives. The doctor tries to help Doon’s father by candlelight. In the morning, Doon and Lina await a roamer said to be arriving. Roamers collect and trade ancient objects in settlements like Sparks. This roamer has a horse, whom Lina loves immediately, and sheep. Doon wants a book the roamer has; Lina trades a match for it. The pages are mostly missing, but a smudged note specifies, “For the people from Em” (31), under a title, Directions for Use. Convinced the book is from the Builders, Doon decides to return to Ember to find whatever the Builders wanted the Emberites to use. He asks Lina, who misses Ember and her messenger job there, to accompany him. She is not sure if the quest is sensible, but she agrees to go.

After a long day’s journey, Lina and Doon find their way back into Ember. Almost immediately, Doon is taken captive by a family, the Troggs, former roamers now living in the city, which the father, Washton Trogg, has renamed Darkhold. Trogg is fascinated by the city’s sporadic light from its dying generator. He forces Doon and another captive, a younger boy Trogg calls Scawgo, to loot Ember’s houses. Trogg has a large diamond he found near the cavern’s entrance; he believes it is a jewel that will someday make his family wealthy and powerful. Doon realizes the diamond is the invention the Builders left for the Emberites.

Meanwhile, Lina escapes Ember before the Troggs see her. Outside, she encounters Maggs, the roamer who traded the Directions for Use, who is Trogg’s sister. She shows Lina the steel-lined vault where her brother found a large diamond and the Directions. The next morning, Lina sets out to return to Sparks for help in rescuing Doon, but Doon has escaped his captors, dismantled the generator for good, and taken the diamond. He finds Lina, but she is surrounded by wolves. Doon throws the diamond to scare them off; it shatters. Mourning its loss, Doon is dispirited. Then he realizes there may be more of the invention; he and Lina study the vault until they find a switch that opens a tremendous cache of a thousand more diamonds.

Back in Sparks, Lina and Doon discover that the diamonds store energy when charged in the sun. Attaching an old light bulb to a diamond creates a bright light. Lina and Doon reveal their discovery to a volunteer crew from Sparks planning to take the remaining food and supplies from Ember. Using the safe, strong lights, teams collect and remove everything they can. Lina says goodbye to her beloved city.

Back in Sparks, the diamonds create light that makes reading and working in the dark possible. The food stores from Ember help Sparks get through the winter. The Troggs, who left the permanently darkened city to return to roaming, are invited to stay in Sparks. Lina acquires a horse and becomes a messenger between Sparks and other settlements, and Doon makes new discoveries using the diamonds. Their work helps Sparks and other villages grow and develop; their legacy expands to future generations, whose towns and cities develop through the use of power from the sun and other sustainable practices.