From the back of the English/European PS2 case:
In Water Drop village, a place teeming with nature, live a family of four.
One day during summer vacation, I set out on a journey. A journey to find the legendary River King, wherever it man be... And... so did my little sister! And Dad! Even Mom set out on a journey, too!!! The personal journey of each member of that family now begins.
Dogs and sheep and other animals will block your path through the land. You can obtain bait from various locations throughout the map, os be sure to use Search whenever you spot a suspicious-looking location.
You can cook and eat the fish you catch. In order to cook, you need cooking recipes.
You can sell the fish you catch to the fish shop and earn money. Once we've saved up some money, let's go shopping for fishing tackle and items.
Once you have your tackle, head for your fishing point. Master live bait fishing, lure fishing, and fly fishing, and fish up a variety of fish.