In a vast universe filled with various intergalactic species, the Guardians of the Universe have established an elite peacekeeping force known as the Green Lantern Corps, warriors who harness the power of green rings fueled by willpower. When the feared enemy Parallax threatens the balance of power within the universe, the Corps encounters its biggest challenge yet. Abin Sur, one of the Corps' most esteemed members, is fatally wounded by Parallax and crash-lands on Earth. With his last breath, Sur's ring selects an impulsive and cocky test pilot named Hal Jordan as his successor, making him the first human to join the Green Lantern ranks.

Struggling to come to terms with his newfound powers, Jordan is initially reluctant to take on the responsibilities of being a Green Lantern. However, as Parallax's reign of terror spreads closer to Earth, he must quickly master the abilities of the ring and the principles it represents. By his side is Carol Ferris, a skilled pilot and Jordan's childhood friend, who sees potential in him that he cannot see in himself. Meanwhile, Dr. Hector Hammond, a scientist and an old acquaintance of Jordan, is transformed and corrupted by exposure to Parallax's essence. As Jordan learns to harness the power of the Green Lantern, he must confront Hammond and the growing might of Parallax, while also overcoming his own doubts and fears to protect not just Earth, but the entire universe.