When you get to the North Sandy Desert, you will be greeted by a Scottish Terrier named Sayir. He has a task for you that will help you get to Dry Valley.
The Quicksand Stick
Sayir tells you that he and a group of other dogs found a Quicksand Stick, which would take away the sandstorm, but he lost it. He asks you to find it again for him.
Sniff around, and you will pick up a pawprint trail. You can follow it or run along the west side of the map, and you will find a cave. Use 
to search it, and you will find the Quicksand Stick. Take it back to Sayir, who is standing by the entrance to Gigili Village.
Sayir takes the stick and uses it to get rid of the sandstorm and the swirling sand blocking the path to Dry Valley. He thanks you, and tells you that you can get there now. Petasi tells you that you can go to Rune Village, or you can go and help all the other troubled dogs first.
Life is a Carnival
Linda in Snow Village will have a question mark above her head. If you talk to her, she will tell you that she has twisted her paw. She tried to visit Dr. Potan's clinic, but thanks to you, he's in Puroro Town instead of at his clinic, so Linda couldn't get treated. She wants you to get her a Medicinal Herb to make her better. You can give her one from your inventory if you have one already, but if you don't have one or simply don't want to give one of yours up, you can go to the Item Shop and buy one. When you have one, talk to her again. She will thank you and use the Medicinal Herb.
After this, Ohlala, if you have already started this mission, will ask for a dancer and you can suggest Linda now!
Challenge with McCoy
When you go to Rune Village, go near the entrance to Rune Canyon and McCoy will meet you. He says that he'll challenge you to a game of soccer and then he'll follow your orders if you win. If you beat him, he hands over the Victory Gang Badge of McCoy.
Petasi says that he thinks you beat all the Victory Gang Dogs.
Victory Gang' Leader
Go up to the door of the Victory Gang Dogs' Hideout in Pupsville. Inside, most of them are there. They are still growling, and Petasi says that if they want more, bring it on! But after a few seconds, they drop their heads and admit that they lose. They thought no one could beat them. They ask if you want to be their leader, because if you say no then they'll only end up fighting over it again. Say you want to be the leader when the choice comes up, and then they ask you to say a speech. It simply turns out as "woof, howl" and they seem to understand whatever it is you said.
Petasi then says that you should take a look in Rune Caverns. There is someone who needs your help in Rune Village.
Present from the Daughter
Tancredi, a Pug, will be standing outside his house in Rune Village with a question mark over his head. If you talk to him, he will tell you that he lost his hat in Rune Caverns. It was a special hat, because his daughter gave it to him. He has to get it back! He teaches you the smell, and then says that there are Cobras in Rune Caverns, so one of them might have made off with it.
When you get to Rune Caverns, go along the path for a while and you will come to a big round area with a Cobra at the other end, in the small gap which leads to a strange statue. This can be tricky but wait until the cobra is facing away from you (or until it goes to sleep) and walk up behind it. Bark or howl, and it will drop the hat. Take it back to Tancredi.
He thanks you and says that you might have seen the statue in there. Apparently, if you put a Sniff Master Medal in the gap, it will unlock a path to somewhere. Petasi says that he's never heard of a Sniff Master Medal, but Tao might know something about it. He says that you should go and see Tao.
Second Book of the Sniff Master
If you go and talk to Tao, he will tell you that he has told you about the Sniff Master Medal before. You needed to find the first and second books of the sniff master. He thinks that you are ready now, and says that you should go and look for the Second Book of the Sniff Master in Rune Village.
When you get to Rune Village, sniff around behind the inn and you will find the Second Book of the Sniff Master. Take it back to Tao.
He congratulates you, and then says that you should check on the Anc Tree.
If he says you aren't able to advance yet, you haven't learnt enough smells from your last visit. As such, you will have to search for different smells first.
Growing an Anc Tree 4
Go to the centre of Pupsville, and you will see that the Anc Tree is now fully grown. Petasi is pleased and says that now he can go back to the Land of Ancs! He then tells you that his queen said he could go back, but that doesn't mean he has to right away. You are shocked, and he asks if you wanted him to leave. After you shake your head, he decided to stay until you have been able to cure your sibling. He then says to go and see Tao.