From Guild Wars 2 Wiki
PROGENY TIP: Rescue the trespasser frozen by a YETI!
— In-game description
- From the checkpoint right before the yeti, head forward to the hill and take a right. Jump to the wall and use the Wooden Whistle to play the Gatekeeper's Lullaby (3-3-2-3-3-1) to open Hidden Room #17. Use the whistle again to play the Shatter Serenade (1-3-3-1-3-3) to shatter the ice around the Raccoon. Speak to the raccoon to exchange the cheese for cake.