Catherine is a violent and disturbed young lady who is shot down by the government in one of her escapades. She wakes up in a training facility and is taught to use weapons, combat, and is put through heavy endurance training. When she is done, she is given the code name "Black Cat". Catherine is now an assassin for the government and is very good at it but she soon finds a boyfriend and is caught between her love for him and her deal with the government

周美诗（彭丹 饰）是电台主持人，某日，一位自称“饿狼”的听众打来电话，声称自己要报复社会，火烧医院。第二天，周美诗看报纸得知果然有一间医院发生了火灾，不寒而栗的她找到了身为警察的嫂子（倪淑君），向其求助，却遭到了王探长（王敏德 饰）的嘲笑。 之后，周美诗又接到了饿狼打来的电话，这一次，饿狼竟然告诉周美诗她已经成为了自己的下一个目标。王探长奉命在周美诗的身边保护她的安全，而话不投机的两人因为之前的误会和恩怨闹出了许多的笑话，但随着时间的推移，勇敢正直的王探长渐渐捕获了周美诗的心，而饿狼亦在警方的缜密设计之下最终落入了法网。