Seven foot gentle giant Barney Emerald is drugged and robbed while on holiday in Pattaya. He befriends two Thai sisters, one who can speak English, another who is a Muay Thai kick- boxing champion, and stays with them until he can recover his passport. After eating some spicy "somtum" at their mother's restaurant, he accidentally demolishes the place. They discover that when Barney eats the spicy "somtum", it has a physical reaction, sending him into a raging and violent martial-arts frenzy. The girls use the somtum to control Barney's powerful reactions to earn back his money and take down the local crime lords.