Two parallel narratives follow John Hackett, a time-dilated astronaut who witnesses humanity's evolution across trillions of years, and Mela, a young woman struggling to survive as her engineered world is consumed by an unstoppable erosion known as the Tide. Interweaving grand cosmic speculation with intimate human drama, the story explores the persistence of memory, the fate of civilizations, and humanity's place in a vast, indifferent universe.

Reader Review Summary

Set across vast stretches of time and space, the novel interweaves two main storylines: John Hackett, a 22nd-century astronaut who embarks on a relativistic journey to Andromeda and back, experiencing time dilation that propels him millions, then billions, and ultimately trillions of years into humanity’s future; and Mela, a young woman living on one of a thousand engineered Earth-like planetoids in a far future, whose world is being inexorably eroded by a phenomenon called the Tide, with only thirty years left before total destruction. Hackett’s narrative explores the evolution of humanity and civilization across cosmic epochs, while Mela’s story focuses on survival, family, and societal collapse as her shrinking world faces a refugee crisis and existential despair. The two threads run in parallel, with their connection only revealed near the end, and the book is characterized by its focus on “Big Ideas” such as the Fermi Paradox, deep time, and the ultimate fate of humanity and the universe. The structure alternates between the two protagonists, with Hackett’s sections spanning cosmic history and Mela’s providing a more intimate, ground-level perspective on apocalypse and endurance.

Readers praised the novel’s ambitious scope, particularly its depiction of deep time and the evolution of humanity over trillions of years, as well as the detailed world-building in Mela’s sections. Many found the scientific speculation and treatment of concepts like the Fermi Paradox and the collision of galaxies to be thought-provoking, with some highlighting the afterword and technical notes as valuable additions. The contrast between the cosmic scale of Hackett’s journey and the personal, emotional struggles of Mela and her family was noted as a strength, providing both grandeur and human stakes. Several reviewers appreciated the evocation of classic science fiction traditions, comparing the work to authors like Arthur C. Clarke and Olaf Stapledon, and found the exploration of societal and existential themes, such as forced migration and the end of worlds, to be compelling.

Criticisms centered on the book’s pacing, length, and character development. Many readers found the dual narrative structure disruptive, with frequent switches between storylines making it difficult to become fully invested in either thread. Hackett’s character was often described as one-dimensional, with his motivations and emotional depth questioned, and some felt that the far-future humans he encounters were implausibly unchanged over immense timescales. Mela’s storyline, while generally better received, was sometimes seen as slow to start or underdeveloped in its exploration of the psychological impact of her world’s demise. The resolution of the two narratives was viewed by some as forced or anticlimactic, and several reviewers felt that the novel’s “Big Ideas” were not always integrated smoothly into the plot, leading to a sense of superficiality or missed potential. The book’s length and density were also cited as barriers to enjoyment, with some readers struggling to finish.

The novel was published in early 2022, received over a thousand ratings with an average of 3.93 out of 5, and was longlisted for the Locus Award for Best SF Novel. It is a standalone work, though the author is known for sequels and recurring themes. The book is available in both print and audiobook formats, with the audio version featuring dual narrators for the two main characters. The story incorporates elements of hard science fiction, space opera, dystopia, and time travel, and includes references to real scientific theories and debates. The author, Stephen Baxter, is recognized for his prolific output and for writing in the tradition of classic British science fiction, often prioritizing speculative concepts over character-driven storytelling.