Meet the Bouncer
When you unlock the Oasis in Stardew Valley, you will also gain access to Sandy‘s shop. In the back right corner of her shop, you will notice a character guarding what appears to be the entrance to the back room of the shop. If you are interested in exploring this area, you will need to complete a series of quests in order to remove the bouncer from the doorway.
Bus Stop
In order to unlock these quests, known collectively as The Mysterious Qi quest, head to the bus stop and enter the tunnel on the left. Inside the tunnel, there is a lock box that you can interact with.
“It’s a battery-powered lockbox. Unfortunately, there’s no battery in it.”
To complete this section of the quest, you will need to place a battery pack in the box. To get a battery pack, you can befriend Pam to get one sent as a gift, craft lightning rods and wait for a storm, buy one from the Traveling Cart, or use the reward from the children’s bundle (remixed) in the community center.
Train Station
After placing the battery pack in the lockbox, you will receive the instructions for the next step of the quest. You will need to place a rainbow shell in a box on the train platform at the train station. This box is located at the train station to the north of Robin’s shop.
You can find a rainbow shell on the beach in the summer (or any season but the chances are much less). It can also be found in the Traveling Cart or as a gift from Demetrius.
Mayor Lewis’ Fridge
After placing the rainbow shell in the box, you will get a quest to place 10 beets in Mayor Lewis’s fridge. Make sure you put them in the fridge. Do not give them as gifts to Lewis directly because this will not count.
Beet seeds can be purchased from Sandy’s shop in the Oasis. You can plant these seeds in the fall or in the greenhouse. They take 6 days to fully grow.
Sand Dragon
In the Oasis, you may have seen the skeleton of a dragon. The next step in this quest requires that you place a solar essence into the mouth of the dragon.
Solar Essence is a monster loot drop. You can find them by slaying ghosts, iridium bats, metal heads, haunted skulls, squid kids, mummies, hot heads, and blue squids. You can also purchase solar essence from Krobus for 80g each.
Once you have your solar essence, place it into the mouth of the sand dragon.
Farmer’s House
The final step of this quest requires you to return to your farm. On the outside of your house, where the lumber pile is located, is where you need to go. When you click on the lumber pile, you will receive your club card. This will give access to the casino.
Casino
When you return to the desert, go into the store and talk to the bouncer. When you talk to him it will prompt you to show him your club card. He will move aside and now you can now enter the back of the oasis. This room is a casino where you can gamble on slot machines or play blackjack in order to earn qi coins (which can also be purchased in the casino).
Qi coins will allow you to unlock new rewards that can only be obtained in the casino.
