Usotoki Rhetoric is a very cute period drama set in the 1940's about a peppy detective named Soma Iwai (Ouji Suzuka) with an intuition for observation and details, who, though a competent detective, is always struggling with debts and looking for his next paying case!
Ouji Suzuka, Ryosuke Mikata
Meanwhile a shy but sincere young woman named Kanoko Urabe (Honoka Matsumoto) has arrived in town. Though she tries to hide it, she has the uncanny ability to tell when anyone is lying! Because of this "curse", she has been shunned by the people in her small hometown, and has been more or less forced to move. Making her way to the big city, she can't get a break and passes out from hunger!
This when Detective Iwai finds her, and takes her under his wing, giving her food to eat and a place to sleep for the time being. The next day, she helps him with his work as a sort of assistant.
Unfortunately for Urabe, during the investigation, she inadvertently uses her lie-detecting abilities when confronted with the slick-tongued culprit, and though this helps catch him, it causes Iwai to learn of her powers at last. 
Thinking Iwai would be abhorred of her curse, Urabe attempts to leave town, but unlike the folks back home, one thing a struggling detective in town can really USE is someone who can tell the difference between someone telling the truth or fibbing, and he hires her as a permanent partner immediately!