Sasha Wass and Jeremy Dein investigate a gang-related murder in Clapham Common in 1953 that left one teenager dead and another man sentenced to hang. What appears to be a fistfight masks a more violent clash - someone has a knife. Three men are stabbed, and 17-year-old John Beckley later dies from his injuries. Several young men were initially arrested and charged, but only one - Michael Davies - was found guilty of murder and sentenced to death. However, Michael was never executed - his sentence was reduced to life imprisonment. Now Michael's niece, Sharon, and family friend Ann are looking for closure. Michael protested his innocence on his release from prison, but he was never exonerated - can his relative finally clear his name? Sasha and Jeremy investigate possible murder weapons and re-examine key evidence given by eyewitnesses. Can they uncover enough new evidence to bring this case before a Crown Court judge and convince him that the original conviction was unsafe?