I suspect this is a novel you will either find fascinating and will stay with you, or it will be boring and you will not make it through. It is overlong, and could do with some editing. It can be thought of as science fiction, but really has less of an emphasis on the technological, serving as an expansive meditation on biological and psychological speculation on Earth’s life and connection with the universe.

The novel develops in five sections, with an epilogue. The story centers on Leigh, a marine microbiologist who is interested in algae, both as a food source and as an early version of life on Earth. Leigh’s family life was troubled: a physically abusive father, whose own life goal was thwarted, and appears to take out his frustrations on Leigh; an emotionally distant mother, a academic mathematician, who fails to rescue Leigh from the abuse; and Helen, Leigh’s younger sister, a close playmate until Leigh reaches about nine years old, when she seems to experience a crisis and an epiphany, discovering her life’s work and its means of saving her from this family situation. The author spends a great deal of time developing Leigh’s back story, making the reader ponder its significance to the greater story.

As a post-doc, Leigh assists an expedition in the south Atlantic Ocean, exploring a recently discovered trench along shipping routes, far from any land. Leigh and the other divers experience strange dream states, fever, time loss, and an extraordinary pull to return to the trench. At this same time, four separate research teams around the globe have amazing insights into a “power” that could lead to the possibility of interstellar human travel, the long-sought means of propelling a spaceship through our solar system and beyond at speeds far exceeding 11gs. Scientists receive these insights in a similar mental state as the divers at the trench. Meanwhile, Leigh is hired by a government contractor to develop algae as a food source for long duration space travel. She is later picked for one of three teams readied for a journey to the outer reaches of our solar system, and it is her group that ultimately go. This journey is motivated by the observation of a peculiar object scientists call Datura, at first thought to be an asteroid, on track to collide with Earth, later seen speeding away out of the solar system. It is believed that it has made contact with Voyager I, the Earth’s probe sent out in the seventies, when a digital message is received similar to the message the probe was sending out; but the message originates far further out in space, beyond where Voyager was thought to be at that time. Leigh’s space journey is meant to chase Datura, and attempt contact.

Many questions swirl around these discoveries: did we receive the insight for the “power” from aliens, and is Datura their lure to make contact? Or does Datura have other origins and purposes? There are many cycles in the plot, algae as an early life form, serving as food for advanced life, some forms of algae when ingested inducing psychedelic experiences, the “power” coming to scientists as a form of psychedelic experience. Datura is a circular form, inscribed with patterns of circles. The space ship we send to follow is also circular, mimicking Datura’s design.

When listening to an interview with the author, he mentioned that the Gaia hypothesis influenced his thinking about this novel. The hypothesis in brief ”proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.” <https://en.wikipedia.org/wiki/Gaia_hypothesis> One may think of this as the Earth being one large organism, all life forms evolving in coordination. This novel, when considered in this light, proposes interesting questions about what Datura is, the true relationships of life on Earth, and whether we are ever likely to explore beyond our solar system. MacInnes stimulates these questions, but leaves the reader to contemplate their meanings.

This sort of speculative novel is either going to interest you and stay in your mind, or leave you cold. It in part depends on why you read. If human relationships and character development are more important for your enjoyment, this novel will feel cold and unappealing. If you are stimulated by a novel that ponders big questions, at the expense of warm human relations, you are likely to find this fascinating. To each reader, their book.