Harry (Clint Eastwood) is a senior police officer in San Francisco, USA. The police station always throws him some difficult cases, and he does not hesitate to use some illegal means to solve the case. Therefore, he got a nickname-"Dirty Harry". An indiscriminate shooting monster appeared in San Francisco. While the first victim was killed, the murderer left a threatening letter demanding $100,000 in cash. Otherwise, he would shoot a citizen every two hours. As the number of victims increased, the incompetent government decided to compromise with the murderer, but Harry could not accept such a compromise. He acted without authorization and arrested the murderer, but also led to the death of the hostages. What he did not expect was that the murderer, who was finally caught with difficulty, escaped the justice of the law because of mental illness, and then intensified his efforts to hijack a school bus full of children. This time, the angry Harry could no longer endure it. He began to deal with the murderer and fired the bullet that represented justice at the last moment.