“Secrets Within Side Quest” is another fairly short side quest that you can be done quickly for some unique rewards in Zelda: Tears of the Kingdom.
You need to help out an NPC named Pulcho here who will reward you with Zonai Devices at the end. These devices may include Steering Stick, Big Wheel, Balloon, Small Wheel, Rocket, and Fans.
How to start Secrets Within in Zelda: TotK
Make your way into the Akalla Highlands and then find Pulcho at coordinates 3802, 1567, and 0091. He will be next to the Device Dispenser on the western banks of Lake Akkala.
Speaking with Pulcho will start the “Secrets Within” side quest in Zelda: Tears of the Kingdom.
How to complete Secret Within in Zelda: TotK
When you talk to Pulcho, he will ask you about the Device Dispenser and how it works. After the dialog, you can head towards the Device Dispenser and place five Zonai Charges on the pot.
This will cause the Dispenser to move and provide you with all of its contents which are Zonai Devices, used in the construction of carts and makeshift planes.
If you don’t have Zonai Charges with you, Zonai Weapons can be used for this purpose but they will give you only some Zonai Devices.
Once you are through with this objective, Pulcho will give you the locations of other Device Dispensers. One is in Kakariko Village and the other is in Digdogg Bridge.
He will also reward you with a Sundelion and tells you that the Scientists at Kakariko Village can tell you about the Sundelion.
That is all there is to complete the Secrets Within quest in Zelda: Tears of the Kingdom.