The city girls include : Royal American ( Kathy Uyen ) , Tuyet Dung ( Thuy Nga ) and Ngoc Vy ( Hoang Oanh ) bumped into each other while sitting together boat. Each of her own purpose for the trip , but they decided to make friends to enjoy the happy moments in the isle . After a night of partying “drop door ” , the three wake up in the boat with the ragged shape and clean forget what happened to me the day before. Trip down ” what has happened ” about their group’s fall resulted in itinerary are gangsters chase group .