Song Yu appears to be a failing student at the bottom of his campus class, but is actually the legendary hacker "G" who wrote the "Hide and Seek" virus. Due to his grandfather's dying instruction to "keep the sharp blade in its sheath," he keeps a low profile and endures year after year. At a cybersecurity competition, Jing University is shut out and humiliated by the Sakura team. After his teammates fail and shift the blame onto Song Yu, he is forced to step forward, using overwhelming technology to reverse the battle situation and achieve legendary status in a single battle. Later, facing the betrayal of his childhood friend Zhang Cheng and revenge from overseas opponents, Song Yu plays along to set a trap, exposes the cheating conspiracy on the spot, leads the team to win the championship, and truly understands the meaning of keeping the blade sheathed.