It's a remarkably well-done portrayal of how Ron Stallworth, the first Black police officer in Colorado Springs, managed to infiltrate the KKK. Starting with fairly routine work in the records room, he’s reassigned by his boss to handle a local black student group headed by Patrice Dumas. Dumas has arranged for civil rights activist Kwame Ture to speak, and Stallworth is tasked with making sure everything proceeds smoothly. Simultaneously, he responds to an advertisement in the newspaper and finds it surprisingly easy to gain access to the KKK’s activities through phone calls. A difficult in-person meeting becomes necessary, so he teams up with Flip Zimmerman, a Jewish colleague familiar with racial insults, to handle it. Zimmerman takes Stallworth's place, and his initiation into this group of deeply violent and wary people turns out to be quite dangerous. Spike Lee guides us on a tense and often gripping story as these men become increasingly drawn into cultures they both come to comprehend and grow to despise. The film’s pacing is excellent, with the sense of threat steadily building throughout. Washington and Zimmerman are strong performers in their roles, and they're backed up by Laura Harrier (Dumas), Topher Grace as the repugnant KKK leader David Duke, and Corey Hawkins (Kwame Ture). The blatant ignorance and bigotry on display are shocking, and the two and a half hours pass quickly.

Source on TMDB