How to Read The Cogheart Adventures in Order
The Cogheart Adventures, written by Peter Bunzl, is a linear, chronological narrative set in a steampunk Victorian England. The story follows a core trio of characters as they mature and face increasingly complex mysteries. Because the timeline of the books flows directly from one to the next, the publication order and the chronological order are identical. For the best experience, you should read the books in the exact order they were published.
- Cogheart (Published in 2016)
- Moonlocket (Published in 2017)
- Skycircus (Published in 2018)
- Shadowsea (Published in 2020)
The Cogheart Adventures Books in Detail
1. Cogheart (2016)
The adventure begins in 1896. Lily Hartman is a strong-willed boarding school student whose life is upended when her inventor father, John, disappears after a tragic zeppelin crash. Rumored to be dead, John leaves behind secrets that a group of sinister, silver-eyed men are desperate to steal. Lily soon discovers that she is being stalked and must flee for her life. Alongside Robert Townsend, a clockmaker's apprentice, and Malkin, a sarcastic mechanical fox (known in this world as a 'mechanimal'), Lily sets off to find the truth about her father's fate. Along the way, she uncovers the mystery of the 'cogheart'—a unique clockwork invention that beats inside her own chest.
2. Moonlocket (2017)
Set eight months after the events of the first book, the sequel takes place during Queen Victoria’s Diamond Jubilee in 1897. The focus shifts toward Robert's mysterious past. When a notorious jewel thief named Jack Door (the 'Jack of Diamonds') escapes from prison, he seeks a hidden treasure linked to a moon-shaped locket. Robert discovers that this locket holds secrets about his long-lost mother. Together with Lily and Malkin, Robert must solve the clues before the dangerous criminal catches up to them, navigating a festive yet perilous London.
3. Skycircus (2018)
In the third volume, Lily receives a mysterious invitation to Slimwood’s Stupendous Traveling Skycircus, along with a notebook that belonged to her late mother. Eager to learn more about her mother’s past, Lily, Robert, and Malkin travel to the circus. However, they soon realize the skycircus is a trap. The ringmaster is kidnapping 'hybrid' children—those who are part-human and part-mechanical—to exploit them as circus attractions. Held captive in the sky, the friends must work together to engineer an escape while confronting deep questions about identity, agency, and differences.
4. Shadowsea (2020)
The final book in the tetralogy takes the adventure across the Atlantic to New York City during a freezing New Year’s Eve. Lily, Robert, and Malkin encounter a boy named Dane who is held captive and speaks of a deep undersea secret. Their search leads them to the 'Shadowsea,' a covert underwater facility. There, they must stop a vengeful professor utilizing a dangerous reanimation machine. This concluding chapter is a bittersweet and action-packed finale that brings the characters' personal growth and the series' overarching mystery to a satisfying end.
Key Characters in the Series
- Lily Hartman: The brave, hybrid heroine of the story. Lily has a mechanical clockwork heart created by her father, which gives her unique qualities but also makes her a target for those who want to exploit her design.
- Robert Townsend: A talented clockmaker's apprentice who becomes Lily's loyal friend. Over the course of the series, Robert grows from a timid assistant into a courageous hero while uncovering his family's history.
- Malkin: A red mechanical fox (mechanimal) designed by Lily's father. Malkin is highly intelligent, fiercely loyal, and provides comedic relief with his cynical, sarcastic remarks and love of biscuits.
Steampunk World-Building and Themes
Peter Bunzl's universe is a rich blend of Victorian historical details and retro-futuristic science fiction. The sky is dotted with magnificent steam-powered zeppelins, and Victorian London is populated by both humans and automatons. In this world, mechanical servants and animals—collectively known as mechanimals—run on clockwork keys and gears. Beyond the fast-paced adventure, the series explores significant themes. Lily's status as a hybrid child serves as a metaphor for identity, belonging, and bodily autonomy. The books touch on ethical questions surrounding technology, what it truly means to be human, and the value of deep, unconditional friendship in the face of greed and prejudice.
Practical Reader Advice
Starting Point: Always start with the first book, Cogheart. Because the characters age, build relationships, and reference past events, jumping into the sequels without the foundational background will spoil the mystery and dilute the emotional impact.
Standalone Readability: While the individual mysteries in books like Moonlocket or Skycircus are resolved by the end of each volume, the overarching character arcs and development spanning Lily's hybrid identity and Robert's past are highly serialized. It is not recommended to read them as standalones.
Age Recommendation: The series is written for middle-grade readers (ages 9 and up). It contains suspenseful action, gothic atmosphere, and dark villains, but maintains a hopeful tone suitable for younger audiences. Adults who enjoy light steampunk adventures will also appreciate the clever world-building.
Other Works by Peter Bunzl: Once you finish the series, you might want to check out Peter Bunzl's other middle-grade books. These include Magicborn and Glassborn, which form a fairy-tale-inspired historical fantasy duology, and standalone historical novellas such as The Clockwork Queen (set in 18th-century Russia) and Featherlight. Note that these books are separate and do not take place in the Cogheart universe.