THE release on December 4th of Spike Lee’s “Chi-Raq”, a musical about gang violence on Chicago’s South Side, comes at a poignant moment for the city. Chicagoans are outraged by a pattern of police misconduct that seems to get worse every day. City officials led by Rahm Emanuel, the mayor, are doing their utmost to contain a scandal whose scale they have underestimated. The Department of Justice has announced it will investigate the city’s cops.

The protagonists of the film are feuding members of rival black gangs on the South Side, idiotic policemen, racist military men and a moronic mayor with a short temper. All this will make uncomfortable viewing for Chicago’s leaders as they grapple with the fallout from the release of a non-fiction video showing the execution-style shooting of a black teenager by a white police officer. Mr Lee waded into the upheaval by predicting that “some more heads are gonna roll” after Mr Emanuel fired his chief of police on December 1st. He was right: on December 6th Mr Emanuel sacked the head of the Independent Police Review Authority, which had declared fatal police shootings “justified” in all but one of the 400 cases it had investigated since 2007. The next day the head of Chicago’s police detectives retired.

Some folks in Englewood and other parts of the city suffering gang-violence are refusing to see the film. They think Mr Lee is making money from their misery and don’t recognise their grief, they say, in bawdy musical comedy. Others worry that the film—called “Chi-Raq” because, according to the film, more Americans died in Chicago from 2001 to 2015 (7,356) than in the Iraq war (4,424)—shows their city in too violent a light. It will deter tourists from visiting and business from investing, they say, though neither tourists nor investors spend much time on the South Side, where most of the killing occurs.

In fact “Chi-Raq” is a contemporary take on “Lysistrata”, a comedy by Aristophanes first performed in 411BC, in which Lysistrata leads the women of Greece to withhold sex from their men to bring an end to the Peloponnesian war. Mr Lee takes the story into Chicago gangland, where Spartans, clad in purple and led by a rapper called Chi-Raq (Nick Cannon), are at war with Trojans, wearing orange and led by Wesley Snipes, with a diamond-encrusted patch over one eye. The war escalates with a shoot-out in a nightclub where Chi-Raq performs and an arson attack on the house where he sleeps with his girl, Lysistrata.

The turning point of the film is the murder in broad daylight of Patti, an 11-year-old girl. Her mother Irene—played by Jennifer Hudson, who has lost her mother, brother and nephew to gun violence in Chicago—is inconsolable. Moved by her pain, Lysistrata rallies the women of the Spartan and Trojan gang members and persuades them to go on a sex strike.

The plot then becomes farcical and confusing. At one point, Lysistrata seduces a Confederate-flag loving general called King Kong so that her army of sex strikers can take over his armoury. The humour is clunky—the sexually aroused general, clad in Confederate-flag underpants, mounts a civil war cannon and is blindfolded and handcuffed by Lysistrata. But the film is saved by its creative use of iambic pentameter and urban slang, rap and the introduction of Dolmedes, a one-man Greek chorus not in the original play, who pops up at regular intervals in brightly coloured suits to fill in the audience with context. “Police siren every day/People die every day/Mommas cry every day/Fathers tryin’ every day” goes Chi-Raq’s prologue.

However bonkers his storyline, Mr Lee’s film offers some hope. Lysistrata and her women persuade the Spartans and Trojans to surrender their weapons, which inspires others around the world to do the same. Fortune 500 companies promise jobs for everyone and the South Side gets a trauma centre named after Emmett Till, a black teenager from Chicago lynched in Mississippi in 1955. Even the wayward Chi-Raq eventually redeems himself. Perhaps the mayor would enjoy it after all.