For centuries, a group of powerful elite teams have maintained the peace of the vast universe. Each of them has a green energy ring, and the green light is the source of their power. They are called the "Green Lantern Corps." But suddenly one day, Green Lanterns in various parts of the universe have been attacked and killed. It turned out that the evil devil Perry Lex, who had been silent for many years, awakened. He wanted to rob the Green Lanterns of their green energy source, so he launched a universe-wide hunt for Green Lanterns. At this time on Earth, Hal (Ryan Reynolds), a test pilot with extraordinary talents but pretentious, accidentally obtained the green ring of the Green Lantern who fell to the earth and became the new Green Lantern protecting the earth. And the humanity it exudes as a human is also a unique breath that other Green Lanterns do not have. In order to defeat Perry Lex, protect the earth and save mankind, Hal needs to overcome his fear and skillfully use his green light energy. As the devil approaches, can Hal defeat the devil and become the greatest Green Lantern?