In 1984, the development of nuclear submarine at a blue "major international leak case, a young security inspector Ma Dong thought is agile, rebellious, was ordered to defend the identity into 202 military factory of secret investigation, to play a thrilling" game of cat and mouse with the spy". In this process, Ma Dong fell in love with the Engineer Feng Shuya, but because the task need to pretend indifference to give up this love, and making friends with her marriage to Chen Qiqian. After careful investigation, in one fell swoop uncovered spy organization Ma Dong feats, but Chen Qiqian was killed, the Feng Shuya has his posthumous. Ma Dong very guilty, to the hearts of love is determined to protect the mother and son, he gave up the chance of promotion to become the real security officer, and Mr Shuya animosity is composed of a happy family