Summary from MyAnimeList.net
Tohru Honda is a high school freshman who is having a serious bout of misfortune. Not only was she recently orphaned with the tragedy of her mother's death, but she also has nowhere to live and is currently residing in a tent! However, when her luck to seems to be at its worst, she meets the Sohma family, and is invited to stay with them in exchange for taking care of the household chores.
But it isn't long before Tohru discovers the Sohmas have a deep secret. The family is cursed by the spirits of the Chinese Zodiac, and some of the children born into the Sohma family are possessed by these spirits. When possessed, they cannot be "hugged" by the opposite sex, or they transform into their respective Zodiac animal!
However, this doesn't faze Tohru, who promises to keep their secret. She continues living with them, and her humbleness and thankfulness never wanes. As a result, they come to be very important people in her life, and the Sohmas begin to realize how very lucky they are to have her.
Fruits Basket