Lena Szarka, a Hungarian cleaner, dusts off her detective skills when a masterpiece is stolen from a gallery she cleans with her cousin Sarika. But when Sarika goes missing too, accusations start to fly. Convinced her cousin is innocent, Lena sweeps her way through the secrets of the London art scene. With the evidence mounting against Sarika and the police on her trail, Lena needs to track down the missing painting if she is to clear her cousin. Embroiling herself in the sketchy world of thwarted talents, unpaid debts and elegant fraudsters, Lena finds that there's more to this gallery than meets the eye.