In the midst of dealing with his own personal turmoil and disenfranchisement, former marine sniper John Stewart's life takes an unexpected turn when he is suddenly enlisted by a dying alien to join the Green Lantern Corps, an intergalactic peacekeeping force. Bestowed with a power ring that grants him otherworldly abilities, Stewart grapples with the responsibility and the ring’s capabilities, finding himself as Earth's newest guardian. As he begins to understand the weight of his new role, he discovers the vastness of the universe and the diverse array of creatures and factions that reside within it.

Stewart's induction into the Green Lantern Corps comes at a time of dire crisis, as cosmic tensions are escalating. An interstellar war looms, driven by a powerful new enemy and an unfolding mystery that threatens the balance of the universe. As allies and enemies surface from the far reaches of space, Stewart must navigate the complexities of his newfound position and confront a menacing force that challenges his courage and his commitment to becoming a member of the Green Lantern Corps. With the fate of the galaxy hanging in the balance, the inexperienced Lantern must quickly hone his skills and learn to trust in the power of the ring.