The episode begins with Azudra developing a strategy to strengthen the defenses of Urum Castle and assembling an elite unit to assassinate the human king. Meanwhile, Anne and Helck are informed by a villager that the Great Witch has arrived. They rush to the village, but the witch has already left. However, she has lifted her barrier and is ready to meet with them.

They visit the witch, who informs them that the continent lies to the northwest but warns them of the challenges of the sea voyage. She advises them to catch a Corstag, a creature that travels between the island and the continent, to guide them through a treacherous section of the ocean. Anne and Helck recall catching a Corstag while fishing, and Anne decides to search for it.

The witch warns Anne about the whirlpool of negative emotions within Helck and the potential havoc he could wreak. Anne and Helck prepare to depart, and Piwi, a villager, insists on joining them. Despite Anne's objections, they set sail with Piwi. The witch reflects on the challenges Anne and Helck will face.

At sea, they encounter a massive creature, but Helck manages to escape it. Anne reluctantly agrees to let Piwi stay with them. They release the Corstag into the water, and it guides them through the foggy ocean. They get caught in a storm and a whirlpool but manage to navigate through. A monster attacks them, but Helck remains confident they can overcome it.