"Prince Alexander is haunted and tormented by his memories of the beautiful Princess Cassima. They met at the end of King's Quest V when Alexander's father King Graham freed his family and the kidnapped princess from the wizard Mordack, but have not seen each other since. Alexander can't even find someone who's heard of the Green Isles let alone knows where it is. The magic mirror sends Alexander a vision of Cassima at her home in the far-off Land of the Green Isles, calling out for Alexander. Alexander sets sail for the Green Isles using the stars shown in the vision, but is shipwrecked in a storm. Alexander washes up onshore alone with nothing but the clothes on his back and some ship wreckage."
Source: Wikipedia, "King's_Quest_VI:_Heir_Today,_Gone_Tomorrow," available under the CC-BY-SA License.