Set one moon after the defeat of Slash, the story centers on Moth Flight, the first medicine cat of the Clans. Haunted by strange dreams and visions, Moth Flight often has her head in the clouds, much to the displeasure of her mother, Wind Runner. After her easily distracted nature nearly causes the death of her father, Moth Flight gives up on trying to please her mother and leaves her Clan. However, on her journey, Moth Flight ends up discovering the Moonstone, a mythical rock which allows the living and the dead to communicate. Beneath the light of the moon, the spirits of her fallen kin visit Moth Flight, revealing that she has a greater destiny than any cat could have expected.
The novel was released on November 3, 2015. It was written by Kate Cary.
This novel contains examples of:
- A Day in the Limelight: For Moth Flight, who was a minor character in Dawn of the Clans, but became the main character in this book.
- Ascended Extra: Several characters from Dawn of the Clans are much more prominent in this book than they were in the fifth arc.
- The book's villain, Willow Tail, was initially a minor character in Dawn of the Clans.
- Acorn Fur is much more important here, since she becomes SkyClan's medicine cat.
- Blood from the Mouth: Redcough, a version of green/whitecough that causes cats to cough up blood, is mentioned. At first, Rocky gets it, and near the ending Slate gets it too, and needs Moth Flight to get the cure for her.
- Book-Ends: At the end of The Sun Trail, Clear Sky sends away his son Thunder, who is taken in by the cats of the moor. At the end of this book, when Moth Flight gives up her kits, Clear Sky takes in Honey Pelt and raises him as a son.
- The Bus Came Back:
- Dew is back after her inexplicable absence in Path of Stars, in as good a shape as ever.
- Branch, last seen during Wind Runner's bonus scene, returns to give her a life.
- Distant Finale: The book ends with one for Dawn of the Clans as a whole. The manga at the end shows us Moth Flight dying of old age years into the future.
- Don't Split Us Up: Moth Flight realizes that she cannot raise kits while being a medicine cat, so she gives up her four kits - one to each of the other Clans.
- Dreaming of Things to Come:
- Moth Flight occasionally has dreams of scenes from the first arc (and one from Firestar's Quest), usually related to the nine lives leaders have.
- Micah has dreams about Moth Flight before meeting her. He also dreams about his future as SkyClan's first medicine cat.
- Frame-Up: To make it look like SkyClan is stealing prey from WindClan, Willow Tail plants rabbit bones near the border and claims to have seen Red Claw stealing a rabbit.
- High on Catnip: Moth Flight gives too much catnip to Rocky, causing him to act jubilant and kitlike. He spends the rest of the book asking for more so that he can experience the feeling again.
- Out of Focus: Several major characters from Dawn of the Clans do much less in this book. Lightning Tail only appears for a single page, for one.
- In both Secrets of the Clans and The Ultimate Guide, Wind Runner exiles Moth Flight from WindClan. In this book, Moth Flight's exile is self imposed.
- One of the retcons in the book is a reverse retcon. In Secrets of the Clans, the Clan Founders are stated to have had the star names that leaders usually get, but Code of the Clans changed it, saying that the founders didn't take star names because the tradition hadn't been established yet. In this book, it turns out that the founders had star names after all, although it was a fair bit after the establishment of the Clans that they got them.
- Running Gag: Moth Flight eats a toad early on in the book. For the rest of the book, she frequently worries about eating toads, or hears other characters wonder who would be crazy enough to eat a toad.
- Someone to Remember Him By: After Micah dies, Moth Flight is happy to learn about her pregnancy, because at least she has something left of Micah.
- Vow of Celibacy: Medicine cats in the series can never take mates, and this book explains why. Moth Flight realizes that her kits are a distraction, and she can't perform her duties to the best of her ability with them around, so she gives them up and makes the other medicine cats vow to never take mates.