Overview

We follow Leigh Hasenbosch from a damaged childhood in Rotterdam into a life shaped by science. She becomes a marine microbiologist just as a vast new trench is discovered in the Atlantic, deeper than anything mapped before. Leigh joins the research effort, drawn by the promise of seeing life at its limits. Later, that same curiosity carries her far beyond Earth on a space mission linked to the search for origins, both human and nonhuman. The story moves steadily from the ocean floor to the outer reaches of the Solar System, asking how far curiosity can carry a person.

Writing & Atmosphere

We found the writing controlled and clear, even when the ideas grow huge. MacInnes grounds the science in physical detail, from lab routines and submersible dives to the quiet intensity of space travel. The language stays calm and measured, which makes the moments of wonder feel earned rather than overstated. The book builds atmosphere through accumulation, letting scale emerge slowly.

Characters

Leigh is at the heart of the novel and we came to trust her perspective. She is reserved, focused, and shaped by a difficult family life that never fully loosens its grip. Her father’s instability and her mother’s emotional distance sit behind many of her choices. Around her, colleagues and crew members feel real without taking over the story. They form a working world defined by pressure, ambition, and ethical tension.

Themes

The novel keeps returning to questions of origin and responsibility. We are asked to think about where life begins, how it survives, and what humans owe to the systems that support us. Climate, ecology, and stewardship sit quietly beneath the plot, never shouted but always present. Home becomes a flexible idea, stretching from damaged families to research vessels, and finally to the planet itself.

What Worked

• Big ideas, personal focus: the science always connects back to Leigh’s inner life.
• Convincing science: marine biology and space exploration feel researched and lived in.
• Careful structure: the slow build pays off as the novel widens in scope.

Minor Quibbles

• The middle section moves deliberately and may feel restrained for readers expecting faster plot turns.
• Some scientific transitions are sketched rather than fully explored, which may frustrate harder science fiction readers.

Final Thoughts

We found In Ascension thoughtful and expansive, bringing together deep sea research and space exploration into a single human story about care, curiosity, and consequence.

Rating: ★★★★½☆ (4.5/5)