One day, a terrible thunderstorm, little goat Mei for cover hides in a dark cave, where he meets his friend in misfortune.Struggling with fear and cold, two associates familiar blindly. They become friends and promise to each other, be sure to meet again and come up with a password, " the night the storm." The next day, May surprised to learn that his new friend - none other than cub named Woof! Contrary to parental prohibitions, they become inseparable friends.Desperately trying to save their friendship, Mei and Gav decide to go " Emerald Forest " on a quest in which they could still be friends. But behind them begins the hunt... screen adaptation of the book Yuichi Kimura.