Madam Tic-Tac although deaf and blind runs a coffee bar in the Edgware Road. It is a front for the gang of criminals that she is the boss of. Her young son Luke does not know about this side of her life. A night watchman is murdered during a raid by some of her men and for one this is too much and he decides to give himself up and tell the police about the Tic-Tac gang. The gang member who killed the watchman takes steps to silence the would be informer and to implicate Luke in the murder. Madame Tic-Tac now has to try and save her son.