Deaf secretary Carla is bullied by her mean spirited male colleagues. When they suggest she needs an assistant it seems like the final insult, but, when the first applicant is ex-con Paul she seizes the chance to change her life. Carla covers his mistakes and he, anxious to go straight, reluctantly helps her take revenge on her colleagues. When Paul asks Carla to return the favour, she finds herself drawn into the criminal underworld, ruled by ruthless loan shark Marchand. Recognising her ability to lip-read as a weapon no one will have bargained for, the two set out to see justice done.