Valka: "Thank the stars you're here, [your Viking's name]. The entirety of Berk smells awful and I have called for a drench on sight for whomever or whatever caused it. So far no one has found out where it's coming from but perhaps you have a better nose.
Follow the green stink and find out what's causing the stench."
1- Find what's causing the stench
Gobber: "Shh! You found me, lassie. Please don't throw water at me! I've tried to explain for years that Vikings are supposed to smell this way but no one sticks around long enough to listen."
2- Ask Heather if she knows of a way to clean Gobber
Heather: "It was Gobber! I should've known... and Vikings aren't supposed to smell like that. Gobber has a buildup of grime and that's what is making the terrible smell. Grime is made up of oils that are hydrophobic (resist water) so washing it with water won't stop the stink.
We'll need a surfactant, a substance that reduces the surface tension of oils, so the water can wash it off. One of the best surfactants is soap.
Don't worry, we can make it without the flowery smell so Gobber won't have any problems with Grump. We can add the smell of smoke and metalwork and call it Essence of Blacksmith if that makes him fell better.
For soap making we'll need animal fat, sodium hydroxide and the fragrance oil that we want it to smell like. The animal fat will react with the sodium hydroxide to make our soap. Let's ask Mulch if he has any yak tallow (that's yak fat!)."
3- Get yak tallow from Mulch
Mulch: "Oh! You need some yak fat, do you? I've got a few globs of it here.
I don't think Gobber is right about the Viking smell though. I haven't smelled that bad since a barrel of rotten fish smell on me. Looking back, I shouldn't have asked Bucket to drop what he was doing."
Heather: "Lye water has sodium hydroxide in it to break th animal fat down. I'll explain how this happens when we start making the soap.
Phlegma uses lye water on her farm but right now she's in Berk next to Astrid's house where there's more fresh air. Would you talk to her and see if she has any to spare?"
4- Speak with Phlegma about lye water
Phlegma: "You're a lucky Viking. I have one container left. I use lye water to keep the acidity of my soil within a certain range so that plants and flowers can better grow. If it's too acidic or not acidic enough, the plant cannot absorb certain nutrients.
Also, you can tell Gobber that no Viking should stink like that unless they fall into the fresh manure cart. That's only happened to me once and I swear to Thor I've never soaped myself that hard in my life. "
Heather: "Pee-ew! We need to hurry because I think the wind changed and Gobber's grime is heading your way. Would you come back here and give me the ingredients?"
5- Give the yak tallow and lye water to Heather
Heather: "I'll keep there safe until I've made a fragrance oil that smells like a sooty blacksmith.
Oh man! I can't focus with the smell of Gobber's grime passing by every few seconds and I'll need some time to get the lab ready for soap making.
For now, can you cover the bad smell with a good smell? Click no all 3 stinks to scatter the rose petals. There's no need to worry about the one on Gobber himself."
6- Click the stink to spread the rose petals (3)
Gobber: "Rose petals, eh? I suppose I deserve this for stinking up Berk in the first place. It won't last, you know. Flowery scents are no match for my mighty musk! I hope that we'll be able to deal with my grime before it spreads to other islands. Thanks for your help.