After the Eastern Sea Dragon King lost his wife, he showered a lot of love on his only daughter, Princess Kavalan. He frequently told everyone,“Kavalan is my precious and beloved. I will pick her a husband of noble dragon blood to befit her status.”However, the princess had already fallen in love with someone. He was none other than the brave and mighty ‘General Guishan’.

One day, when the lovebirds met in secret, the princess told the general,“My father is going to betroth me to my cousin, Dragon. What should we do?”Though General Guishan loved the princess very much, and worried that the princess might suffer a life of hardship with him, he wanted to be with his beloved very much. So, he mustered his courage and asked the princess,“Princess, I would like to be with you forever, will you leave with me?”The princess nodded her head in consent, and the pair eloped late at night while everyone was fast asleep, and started a new life on land. The princess and the general led a simple life and gave birth to a baby boy, whom they named “Heping”.

A few years later, something terrible happened. The Dragon King learned of their whereabouts, and sent his army of shrimps and crabs to capture the princess. Then, the Dragon King angrily issued a command to his army,“Flood this plain now.” Immediately, the skies turned dark, and the floodwaters ruined the princess and the general’s beautiful home. The Dragon King held his scepter aloft, and addressed the general and Heping sternly,“I will transform the both of you into islands, so that you will forever be apart.”A ray of golden light appeared and transformed the father and son into two islands. One landed in the waters off Yilan, and the other landed in the waters off Keelung, and they became what we now call Guishan Island (“Tortoise Hill Island”) and “Heping Island”.

Princess Kavalan was heartbroken at losing her beloved husband and son. So, she took out a Magic Green Pearl that her mother had left her, and told the pearl,“Please transform me into a grassy plain, so that I may forever look after my family!”The princess disappeared after uttering the words, and was transformed into the evergreen Lanyang Plain. The Dragon King was overcome with remorse for what he did. So, he cast away his scepter sorrowfully, and turned himself into Jinmian Mountain next to Taipei-Yilan Highway, a mountain forest surrounding the Lanyang Plain.

　　東海龍王自從妻子逝世後，就對獨生女「噶瑪蘭公主」非常疼愛，他常對大家說：「噶瑪蘭是我的心肝寶貝，我要幫她選一個有我們龍族血統的夫婿，才能和她匹配。」但是，公主早就有了意中人，那就是英勇善戰的「龜山將軍」。
　　有一天，兩人私下偷偷見面時，公主對將軍說：「父王要把我許配給龍表哥，怎麼辦呢？」龜山將軍雖然很喜歡公主，卻又害怕公主跟著自己受苦，可是為了能和自己心愛的人在一起，將軍鼓起勇氣對公主說：「公主，我想永遠和妳生活在一起，你願意和我一起離開這裡嗎？」公主點頭答應後，兩人就趁著夜深人靜時，逃離大海到陸地上生活。公主與將軍過著凡人的生活，還生了一個男孩，名叫「和平」。
　　數年後，可怕的事發生了，龍王發現他們的蹤跡，發動蝦兵蟹將捉拿公主，龍王憤怒地對著大軍說：「快製造洪水將平原淹沒。」瞬間，天色變暗，洪水沖垮了美麗的家園，龍王高舉手中的權杖，對著將軍及和平大聲說：「我要把你們變成島嶼，永遠都不能在一起。」這時出現一道金色的光束，父子倆就變成兩座島嶼，一個在宜蘭外海，一個則在基隆外海，也就是現今我們所看到的龜山島與和平島。
　　可憐的噶瑪蘭公主，失去了心愛的丈夫和兒子後，就拿出母親留給她的龍宮寶物「綠珍珠」說：「請將我變成草原，讓我永遠守護著我的家人吧！」說完後公主就消失了，成為終年常綠的蘭陽平原。
　　龍王後悔自己所做的一切，便傷心地丟下權杖，化身成北宜公路旁的金面山，成為環抱蘭陽平原的山林。