Timothy, adopted by the wealthy Snyder family, grows up devoted to his three older sisters — until the day their biological son, Matthew, returns and turns them against him with lies and manipulation. Cast out and blamed for things he never did, Timothy still repays their kindness: he saves them, sacrifices for them, and even secretly volunteers for Project Hail Mary, a mission to save humanity by sending one person with a rare gene into find a new planet. Only after he's gone, do the Snyders discover the truth about Matthew's schemes and Timothy's sacrifices. Thirty years later, Timothy succeeds on Planet Artemis, honored as a hero while his grieving family lives with the cost of their betrayal.