“Mia, look for me when you get out. I'll be waiting. I promise.”
— Grace leaves a note for Mia before disappearing from the boarding school.
Archivist's Choice
On a Sunbeam
Tillie Walden (2018)
Genre
Fantasy / Science Fiction / Young Adult / Romance
Reading Time
300 min
Key Themes
See below
Track Your Reading
Sign in to track this book
In a future where space crews restore old structures, a new recruit joins to find her lost love, a mysterious girl she met in boarding school.
Synopsis
Mia joins the 'Rebuilders' crew, who travel through space to fix old structures. As she adjusts to her new life and meets her teammates, the story often shows her past at Asteria, a secluded boarding school. There, she falls in love with a quiet girl named Grace. Their relationship grows, but Grace suddenly disappears. Mia is heartbroken and determined to find her. Mia's real reason for joining the Rebuilders is to use their resources to track Grace. The crew, including Captain Alma and Charlotte, agree to help. Their search takes them to different planets and uncovers secrets about Alma's past and Charlotte's link to Asteria. Following clues, they find Grace on a hidden, empty planet. The reunion reveals Grace's past and why she disappeared, starting a new chapter for Mia, Grace, and the Rebuilders crew as they build a future together.
Reading time
300 min
Difficulty
Easy
Pacing
Moderate
Mood
Dreamlike, Romantic, Melancholy, Hopeful, Adventurous
✓ Read this if...
You love beautiful, atmospheric art, queer romance, found families, and a unique blend of sci-fi and fantasy with a strong emotional core.
✗ Skip this if...
You prefer fast-paced action plots, clear-cut genre boundaries, or highly detailed world-building explanations over character-driven narratives and visual storytelling.
Plot Summary
Mia Joins the Rebuilders
The story begins with Mia joining the 'Aktis,' a spacecraft crewed by a small group of women who fix old structures across the galaxy. She meets the leader, Alma, the quiet engineer, Charlotte, the lively pilot, Sanda, and the researcher, Grace. Mia quickly learns about space travel and the rebuilders' work, which involves delicate repairs to abandoned cities and monuments. Despite her initial shyness, she starts to connect with her new crewmates, especially Sanda. Mia, however, has a secret reason for joining the Aktis: she is searching for someone from her past.
Flashback to Asteria and the Silent Girl
The story moves to Mia's past, specifically her time at Asteria, an all-girls boarding school. Here, students learn to survive in unique, often isolated places. Mia is initially a loner, but her life changes when a new student arrives, a quiet girl who does not speak and is known only as 'Grace.' Mia is immediately drawn to her. They start spending time together, communicating through gestures, shared moments, and a growing unspoken understanding. This time at Asteria is marked by Mia's strong emotional connection to Grace, setting up a love story.
Developing Love at Asteria
At Asteria, Mia and Grace's connection grows into a deep, tender love. They spend their days exploring the school's unique architecture, sharing meals, and simply being together. Mia teaches Grace to speak by drawing words and sounds, and Grace slowly begins to communicate, mostly with Mia. Their connection becomes the main focus of Mia's world, a quiet refuge from other students and school rules. They share a special moment in the school's abandoned 'fish room,' a place of comfort and beauty. Their love is pure and all-consuming, a secret world they build together.
The Disappearance of Grace
Their happy time at Asteria ends when Grace suddenly disappears. Mia is heartbroken and cannot understand why she left. The school offers no answers, leaving Mia with a huge emptiness. This event changes Mia, giving her a strong desire to find Grace again. Her time at Asteria ends in sadness and a firm promise to reunite with her lost love. This separation drives Mia's future actions and her decision to join the rebuilders, believing it will lead her closer to Grace.
Mia Reveals Her True Purpose
Back in the present, Mia has integrated into the Aktis crew, but her main mission remains. During a quiet moment, she tells Alma, the wise leader, about her past and her search for Grace. Mia explains her love for Grace, her disappearance from Asteria, and her belief that Grace is still out there. Alma listens patiently and reveals that she knows more about Mia's past than Mia realized, and she understands Mia's quest. This revelation strengthens Mia and Alma's bond and changes the crew's dynamic.
Alma's Secret and Charlotte's Past
Alma, seeing Mia's pain and determination, shares a detail about her own history, hinting at a past connection to Asteria and a similar loss. This makes Mia trust her more. Meanwhile, Charlotte, the engineer, shares a painful memory during a rebuilding job at an old family home. It becomes clear that Charlotte's family was lost to a space disaster, leaving her with trauma and a deep fear of losing loved ones. This shared vulnerability among the crew strengthens their relationships and adds depth to their individual reasons for being rebuilders.
The Search for Grace Begins
With Alma's approval and the crew's growing understanding, the Aktis starts to include Mia's search in their rebuilding missions. They visit old, abandoned structures and archives, looking for any information that might lead them to Grace. Mia provides what little information she has, mainly the last known location and the unique circumstances of Grace's disappearance. The crew's combined skills – Sanda's piloting, Charlotte's technical knowledge, Grace's research, and Alma's wisdom – are now partly focused on helping Mia. They find a unique symbol Mia recognizes from Grace's belongings, giving them a real lead.
Following the Clues to a Hidden Planet
The symbol leads the Aktis to a hidden planet, a place of untouched nature. This planet challenges their understanding of the galaxy's history and its forgotten places. As they explore, they find traces of a unique civilization and a connection to the symbols Mia found. The planet seems to be a sanctuary, a place where certain individuals can find refuge. The crew realizes that the 'rules' of their known universe might not apply everywhere, and there are deeper mysteries than they imagined. This discovery gives Mia hope, making her believe she is closer than ever to Grace.
Reunion and Revelation
On the hidden planet, Mia finds Grace. The reunion is emotional, a result of years of searching. Grace, now older, reveals why she disappeared: she is a 'star-child,' a being who can travel vast distances and 'disappear' into space. She explains that her family, also star-children, took her from Asteria to protect her and to live on this secluded planet, where they could be free. Grace's initial inability to speak was due to the trauma of being taken from her family and placed in the school. Mia learns that Grace's family has been watching over her, and that Alma had known Grace's family for a long time.
A New Beginning for All
With the truth revealed, Mia and Grace confirm their love. Grace's family welcomes Mia into their community on the hidden planet. The Aktis crew, having seen this reunion, finds their own bonds stronger and their views broader. Alma explains her long-standing connection to Grace's family and her role in guiding Mia. The crew realizes that their work as rebuilders is not just about fixing structures, but about connecting lost pieces, both physical and emotional. The story ends with Mia and Grace together, and the Aktis crew continuing their journeys, now with a renewed purpose and a deeper understanding of the universe's connections.
Principal Figures
Mia
The Protagonist
From a heartbroken, solitary seeker, Mia evolves into a more confident and open individual, finding her lost love and a new family.
Grace
The Protagonist/Love Interest
From a silent, lost girl, Grace finds her voice and reunites with her true love, embracing her unique heritage.
Alma
The Supporting
Alma's character remains largely consistent as a wise leader, but her past connections are revealed, deepening her role in the overarching narrative.
Sanda
The Supporting
Sanda's character remains a source of levity and support, her loyalty to the crew deepening as they embark on Mia's personal mission.
Charlotte
The Supporting
Charlotte slowly opens up to her crewmates, confronting her past trauma and forming deeper bonds of trust.
Grace (present-day researcher)
The Supporting
Grace's character provides consistent intellectual support and grows in her understanding of the universe's deeper mysteries.
Grace's Family
The Supporting
As a collective, their arc is to be discovered and to welcome Mia, revealing the deeper truths of Grace's origins.
Asteria Students/Teachers
The Mentioned
They serve as a static backdrop, their primary role being to facilitate the initial development and subsequent loss of Mia and Grace's relationship.
Themes & Insights
Love and Connection Across Distance
The main theme of the book is that love can overcome long distances and time. Mia's constant search for Grace, spanning years and galaxies, shows this. Their emotional bond is so strong it goes beyond physical separation, driving Mia's actions. This theme is also seen in the 'Aktis' crew's found family, showing that deep connections are important for survival and meaning in a vast universe.
““I'd waited so long to find you. And I'd wait a thousand more years if I had to.””
Identity and Self-Discovery
Both Mia and Grace go through journeys of self-discovery. Mia's identity becomes tied to her love for Grace and her search for her. Through this, she learns about her own resilience, courage, and ability to love. Grace's journey involves understanding her unique nature as a 'star-child,' finding her voice, and reuniting with her family. The 'Aktis' crew also deals with their identities, shaped by past traumas and their shared purpose as rebuilders, finding a sense of belonging.
““You can build a life out of anything, if you try.””
Found Family and Belonging
The 'Aktis' crew shows the theme of found family. Each member has their own reasons for being on the ship, and together they form a unit, supporting each other. Mia, initially an outsider, is gradually welcomed into this family, finding a sense of belonging that helps her personal quest. The discovery of Grace's 'star-child' family expands this theme, showing that family can be chosen and defined by shared experiences and love, not just blood.
““We're a team, Mia. We look out for each other.””
The Past and Its Echoes
The book constantly mixes past and present, showing how past events affect current actions and reasons. The alternating timelines between Mia's time at Asteria and her present on the 'Aktis' directly illustrate this. The crew's work as 'rebuilders' also involves putting the past together, restoring old structures, which mirrors Mia's emotional journey of piecing together her past with Grace. Charlotte's trauma and Alma's hidden history further show how the past shapes individual lives and group purpose.
““Some things are broken, but they're not gone.””
The Wonder and Mystery of the Universe
The vast, imaginative setting of space, with its abandoned structures, uncharted planets, and unique beings like the 'star-children,' shows the wonder and mystery of the universe. The rebuilders' missions constantly expose them to forgotten histories and unknown things, expanding their understanding of what is possible. The discovery of Grace's abilities and her family's hidden planet shows that there are always new places to explore and deeper truths to find, challenging common understanding and inspiring awe.
““There's so much out there we don't know about.””
Plot Devices & Literary Techniques
Dual Timeline Narrative
Alternating chapters between Mia's past at Asteria and her present on the 'Aktis.'
The story is told through a dual timeline, constantly shifting between Mia's formative years at the Asteria boarding school, where she falls in love with Grace, and her current journey as a member of the Aktis crew, searching for her lost love. This device builds suspense, gradually revealing the depth of Mia's past relationship and the catalyst for her present quest. It also allows for a rich character development, showing Mia's transformation and the enduring impact of her first love on her adult life. The parallel narratives converge as Mia's present-day search directly connects to her past experiences.
The Aktis Ship and Rebuilders' Work
The spacecraft and the crew's mission to restore ancient, broken structures.
The Aktis ship itself, and the crew's unique profession as 'rebuilders' of ancient, dilapidated structures across space, serves as a powerful metaphor. Their work of meticulously piecing together broken remnants of the past mirrors Mia's emotional journey of trying to piece together her fragmented memories and find her lost love. It also symbolizes the theme of healing and restoration, both of physical places and of emotional wounds. The ship becomes a mobile home and a sanctuary, representing the found family aspect of the narrative.
The Silent Girl/Grace's Voice
Grace's initial inability to speak and Mia's role in helping her find her voice.
Grace's initial silence at Asteria is a significant plot device. It immediately sets her apart as mysterious and vulnerable, drawing Mia to her. Mia's patient efforts to teach Grace to speak symbolize their deep connection and the intimacy of their bond. Grace finding her voice not only signifies her growth but also represents her coming into her own power and revealing her true nature as a 'star-child.' This device highlights the profound impact of communication, both verbal and non-verbal, in forming and maintaining relationships.
The Hidden Planet and Star-Children
A secret, uncharted world inhabited by beings with unique abilities.
The hidden planet and the 'star-children' community serve as a fantastical plot device that expands the scope of the universe and introduces a mystical element. It provides the ultimate destination for Mia's quest and the explanation for Grace's disappearance and abilities. This device allows for the magical realism aspect of the story, challenging the reader's understanding of the known world and revealing deeper, ancient truths. It also acts as a sanctuary, representing a place of belonging and acceptance for those who are different.
The 'Fish Room' at Asteria
A magical, abandoned room filled with aquatic life at the boarding school.
The 'fish room' at Asteria is a symbolic location where Mia and Grace's love deepens. It's an abandoned, forgotten space that they transform into their private sanctuary, filled with glowing aquatic life. This room represents the unique, magical bubble of their relationship, a place of beauty and intimacy separate from the rest of the world. Its eventual abandonment after Grace's disappearance underscores the heartbreak and loss Mia experiences, making it a poignant symbol of both their love and its temporary nature.
Critical analysis
Notable Quotes
“Every once in a while, something beautiful just... appears.”
— Mia reflects on the unexpected beauty she finds in the universe, often in abandoned places.
“Sometimes the only way to find something is to lose yourself completely.”
— Eliza offers advice to Mia about her search for Grace, implying the need for letting go.
“You can't fix everything. Some things just have to be.”
— Eliza shares a pragmatic view on life and its unchangeable aspects with the crew.
“It's not about what you find, it's about who you become while looking.”
— The crew discusses the nature of their restoration work and the personal growth it brings.
“You found me. After all this time, you actually found me.”
— Grace's emotional reaction upon being reunited with Mia after years apart.
“The universe is big, but it's not that big when you're looking for someone specific.”
— Mia's determination to find Grace, despite the vastness of space.
“We're not just fixing buildings, we're fixing memories.”
— Eliza explains the deeper purpose of their restoration work on derelict structures.
“Some quiet places are the loudest.”
— Mia observes the profound atmosphere of a seemingly abandoned and silent location.
“You don't get to choose who you love, only if you're brave enough to act on it.”
— Alma offers wisdom to Mia about the complexities and courage required for love.
“There's always a story in the walls, if you know how to listen.”
— The crew's philosophy when exploring and restoring old, abandoned structures.
“It's okay to be lost, as long as you're still moving forward.”
— Mia reflects on her journey and the uncertainty of her path, finding solace in progress.
“The past isn't always what you remember, but it's always part of who you are.”
— Grace and Mia discuss their shared history and how it shaped them.
“Sometimes, the most broken things are the most beautiful.”
— Mia's perspective on the derelict structures they restore, finding beauty in decay.
Quiz
Test Your Knowledge
Ready to see how well you understood this book? Take our interactive quiz with 10 questions.
10
Questions
~5
Minutes
?
Best Score
Key Questions (FAQ)
"On a Sunbeam" tells two interwoven stories: Mia's present-day journey aboard a spaceship crew that restores ancient, derelict structures in the vastness of space, and her past experiences at a mysterious all-girls boarding school where she fell deeply in love with a new student named Grace. Mia joins the restoration crew with the secret intention of finding Grace, who vanished years ago.
About the author
Biography coming soon.
