Project Hail Mary

Ryland Grace, a junior high school teacher with a background in molecular biology, wakes up aboard a starship with no memory of his identity or mission. He gradually recalls that Earth's sun is being dimmed by a microbe called Astrophage, and he is on a desperate mission to Tau Ceti to find a solution. There he meets Rocky, an alien engineer from a spider-like species, and together they discover a predator microbe that can save both their worlds. After a series of challenges, Grace sacrifices his return home to save his alien friend and ultimately ensures the survival of both Earth and Erid.