Project Hail Mary

Ryland Grace wakes from a medically induced coma aboard a spacecraft with no memory of who he is or why he is there, his only companions two dead crewmates in their own recovery pods. Piecing his situation together from ship logs and returning fragments of memory, he reconstructs the crisis that put him there: a microorganism nicknamed Astrophage is consuming the Sun's energy from the inside, and every star near Earth except one, Tau Ceti, shows the same infection, so a coalition led by the blunt and ruthless administrator Eva Stratt has launched a single, one way mission carrying the one man on the project who is both a molecular biologist and, before Stratt drafted him against his will, a burned out middle school science teacher. At Tau Ceti, Grace discovers he is not alone. A spider like alien engineer he names Rocky, whose own home star faces the identical infection, has arrived on a parallel mission from a species with no verbal language of its own, and the two build a shared vocabulary through music and light before identifying Taumoeba, a second microorganism that preys on Astrophage and could save both civilizations, only for Grace's own experiments to accidentally breed a strain that can eat through the containment material his and Rocky's ships depend on. With no way to bring a cure home without destroying Rocky's ship in the process, Grace gives up his own return to Earth so Rocky can carry a working sample back to save his people, and the novel ends sixteen years later with Grace living out his days as a science teacher again, this time among Rocky's own species, having learned from Rocky that the Sun returned to its full brightness, so Earth survived.

Weir writes the whole book as a puzzle solved in real time, one problem after another worked out on the page through orbital mechanics, chemistry and improvised engineering, in the same spirit as his earlier novel The Martian, and readers who enjoyed that book's patient competence will recognize the rhythm immediately. It reads fast despite the science, helped along by Grace's constant, self deprecating narration and by Rocky, whose friendship with Grace across a language barrier neither can fully close is the novel's real emotional center; some readers find the science lectures run long, but few report losing the plot underneath them.