You will need a music box key to fight the boss in "Shipwreck." To get the music box key, you'll need to complete the Cathedral, then go to the Divining House and ask the nice lady to tell you about the queen's lost lover. Then go to the the guy you meet at first when you come to Queens (don't remember the name). He won't be in his shop but there will be a key. That key will open the music box. If you want strategy to beat the ice queen boss, find it on this page.