Two American F-35 Lightning II fighters breach Chinese airspace, causing significant disruption along the coast. Their supersonic speeds generate powerful sonic booms, resulting in damage to an oil refinery and impacting local fishing vessels. In response, Chinese pilot Lei Yu takes to the skies in his Chengdu J-10 to intercept the intruders. Pushing the boundaries of his aircraft, Lei Yu faces the formidable challenge posed by these advanced 5th generation fighters, but ultimately, the F-35s exit the airspace. However, Lei Yu's jet encounters severe engine troubles, including a flame-out during a critical vertical climb, which forces him to execute an emergency landing.
In a debrief, Lei Yu's superiors express their discontent with his aggressive flying approach. He passionately defends his decision, asserting it was the only viable tactic against superior enemy forces. The high-ranking officials contemplate the pressing issue: the vast superiority of foreign 5th generation fighters over their outdated 4th generation models. They highlight that Chinese jet engines are yet to reach a competitive standard against these advanced adversaries.
In a covert operation, China is working on developing the stealthy 5th generation Chengdu J-20 to counter such threats. Commander Zhang Ting extends an invitation to Lei Yu to join the new stealth fighter initiative, which he eagerly accepts. The test pilot team also includes notable members such as Deng Fang (Yosh Yu), Gao Yingjun, Xia Pengfei, Li Xiaohang, and Tong Gan, while Shen Tianran (Dongyu Zhou) oversees the physical fitness evaluations of all pilots.
At the training base, Lei Yu and his fellow pilots undergo intense and demanding training regimes, pushing their physical and mental limits. The J-20's development is still ongoing as the prototype WS-13 Taishan engine has not yet been finalized. They conduct various tests using alternative aircraft to evaluate the engine’s performance before it’s fitted into the J-20.
During a critical flight exercise with Commander Zhang Ting, both pilots experience a thrust failure, which leads to a perilous spiral dive. Lei Yu, sensing the imminent danger, decides to eject, while Ting valiantly manages to regain control and land the aircraft safely. Unfortunately, due to this ejection, crucial flight data is lost, rendering Lei Yu's life-risking action futile.
Subsequently, Lei Yu finds himself grounded and on the verge of being dismissed from the training facility. During this suspension, he dedicates himself to studying the mechanical issues that plagued the aircraft. He devises a proposal for an innovative anti-stall parachute that promises to enhance the safety of test pilots and aircraft, enabling them to gather vital data without catastrophic failures.
On Ting’s final day, he persuades Lei Yu to accompany him for a test flight on the fighter's engine and missile systems. Sadly, calamity strikes as both engines fail during testing, leading to catastrophic overheating. Both pilots agree to eject together, but Ting heroically decides to steer the failing aircraft away from populated areas, sacrificing his life in the process. Following his death, Ting receives a military burial, while Lei Yu resolves to honor his legacy by contributing to the J-20 program.
With Zhang gone, Deng Fang is appointed as the new chief pilot. Despite his father's concerns about China’s ability to independently produce a competitive stealth fighter, Lei Yu refuses to return home, fueled by his determination to support his country’s ambitions.
Driven by a sense of duty, he develops the anti-stall parachute deployment system, rigorously testing it on the ground. Meanwhile, the design team modifies the engine to endure the extreme conditions caused by missile exhaust without failing. In collaboration with the new chief pilot Deng Fang (Yosh Yu), they conduct successful flight tests, where the engine performs seamlessly despite ingesting missile smoke.
However, their next test takes a treacherous turn when a flock of birds strikes the cockpit, incapacitating both pilots. Nevertheless, Lei Yu rises to the challenge, determined to maintain control of the aircraft. Utilizing the newly installed anti-stall parachute, he battles through extreme adversity, proving the viability of the enhancements made.
Eventually, American stealth fighters and drone incursions repeat as they intrude once again into Chinese airspace. In a show of their advancements, Lei Yu and Deng Fang launch their newly completed J-20s, successfully shooting down the drones before confronting the F-35s. Knowing that engaging the American fighters could provoke international conflict, Lei Yu signals a warning to retreat. In a poignant end-credit scene, he and his squadron honor the memory of Commander Ting by performing a heartfelt flyby, releasing colored smoke above a soccer field as a tribute to his son.
