Model engineer Liang Jinyi heads to the Liang'an flight test base with a new fighter jet. Due to successive mid-air engine shutdowns during test flights, she locks horns with flight test squadron leader Xu Duan, who insists that flights cannot resume until problems are ruled out. Through repeated contests and working side-by-side to troubleshoot, the BUAA alumni—who share a hidden past—reconnect. Moving from sharp hostility to quiet affection, they jointly safeguard the safe return flight of the fighter jet.