What happens
Dogberry and Verges instruct the night watch with comically muddled advice about keeping order. While they speak, Borachio and Conrade arrive nearby, and Borachio drunkenly confesses to Conrade how he and Don John deceived Claudio and the prince by staging a false seduction scene with Margaret at Hero's window. The watchmen, eavesdropping, hear the entire confession and arrest both men as criminals, though Dogberry misunderstands the details.
Why it matters
This scene is the play's turning point, though no one onstage fully realizes it yet. The Watch, despite Dogberry's absurd leadership and malapropisms, accidentally stumbles onto the truth that will save Hero. The irony is devastating: while Don Pedro, Claudio, and Leonato are actively deceived by Don John's staged scene, these bumbling constables—dismissed as fools throughout the play—become the instruments of justice. Dogberry's incompetence paradoxically enables truth-telling; his instruction to 'let them go' if they won't stand, and his obsession with written records, means the criminals are both arrested and their confession is documented. The scene reveals that truth doesn't require wit or authority—it requires only attentiveness, and sometimes that comes from unexpected places.
Borachio's drunken confession mirrors Claudio's gullibility: both men are undone by what they believe they see or hear. Yet where Claudio trusts a false visual lie, Borachio carelessly admits a true verbal one. His boasting about earning a thousand ducats, his contempt for 'Deformed' fashion, and his casual recounting of the seduction scheme show a villain secure in his crime—not realizing that justice walks in the form of the night watch. Dogberry's bumbling transcription of the confession ('they have committed false report'; 'they are lying knaves') obscures rather than clarifies, but the Sexton will later straighten it out. This scene demonstrates that even systems designed to fail (the incompetent watch) can succeed if the facts are sufficiently obvious. The criminals are caught not by clever investigation but by their own bragging and the watch's sheer determination to record something, however badly.