Sea Slug

The Fishing Platform
Talk to Caroline on the coast north of the town of Witchaven, east of Ardougne. She will tell you her husband, Kent, and her son, Kennith, are missing and ask you to go to the Fishing Platform to find them. Holgart has a boat that he can maybe take you in.

Talk to Holgart, and he will tell you his ship is in need of repairs. He will ask you to go and get him one swamp paste to fix it up. The best way to get swamp paste is to buy it directly from the Grand Exchange. Alternatively, you could go to the general store in Port Khazard, located south of Ardougne - a guaranteed source. Once you give him the swamp paste, Holgart will appear in a cut scene fixing the boat. Talk to him again to go to the Fishing Platform.

Note: You cannot use swamp tar. However, you can mix swamp tar with flour and cook it on a fire (does NOT work on a range) to create swamp paste.

Investigate
When you arrive, you will notice the odd behavior of everyone as they all seem to be in a zombie-like trance. Do not pick up the sea slugs; they will hurt you!

Look around and find Bailey inside a small room in the southwest corner of the platform. Talk to him, he will tell you about the odd happenings and the hauling up of the sea slugs. Also, pick up the broken glass on the floor there for later in the quest.

Helping Kennith
Pick up some damp sticks close to to the ladder in the north-east corner of the platform, then climb up. Upstairs, in a room on the west side, past the crane, you will find Kennith. He will tell you he is too horrified to leave with all the sea slugs and the strange fishermen. He will ask you to find his father, Kent and help him.

Go back to Holgart and talk to him. He will take you to a deserted island, where you will find Kennith's father stranded. Talk to Kent and he will tell you his story. Then ask Holgart to take you back to the platform. Talk to Bailey to find out the slugs' weakness - they are afraid of heat. He will give you an unlit torch, which he cannot light it himself as it is too damp. Use the broken glass on the damp sticks, which are found near the ladder to dry them, then rub them together to light the torch.

Climb up the ladder again (on the north-east of the platform), go into the room, and talk to Kennith. From outside the room, kick the badly repaired wall to make an opening, and then talk to Kennith again, Rotate the crane to save him, shown in a cut scene. Talk to Holgart to return to shore. Finish the quest by talking to Caroline.

Reward

 * 1 Quest point
 * 7175 Fishing experience
 * Access to the Fishing Platform
 * Oyster pearls