Upon entering, you will meet a new race in EarthBound known as the Tendas. Unfortunately, none of them will speak to you because they are very shy. There is only one Tenda, near the boulder, that will talk to you. He explains that the only Tenda that can lift the boulder needs to overcome his shyness before he will speak to you. Talk to the Tenda Chief and he'll briefly mention a book he can't find, called "Overcoming Shyness".
There are a few things to note about Tenda Village. The hot springs will cure any status ailments you may have accumulated in the Deep Darkness. A Tenda near the cave entrance in the north will let you rest at an inn for free. On the bottom side of Tenda Village is a place with "weird junk" including a trash can that contains a Death Ray. Also, there is a phone here that you can use to save your game.
Head back out to Deep Darkness and Apple Kid will call you explaining that Dr. Andonuts went missing. In the middle of the call, Apple Kid will be kidnapped! As soon as the link goes dead, Orange Kid will call you to let you know that Apple Kid has gone missing. Apparently Apple Kid has the book "Overcoming Shyness" as well. Make sure you have the Pencil Eraser with you and teleport to Winters.
Back at Winters
When you arrive in Winters, Maxwell will let you know that Tony has also gone missing. Be careful because the easy enemies that you faced in the past have been replaced by much more difficult aliens and robots. Use PSI Shield to protect yourself from their devastating attacks if you have to. Head south to the Tessie Watching camp and you'll find out that one of the watchers has been kidnapped too. Use the Bubble Monkey to call Tessie and ride to the south.
Use your Pencil Eraser to bypass the maze (it is more of a convenience than a necessity) and head to Dr. Andonuts lab. Inside, the Apple Kid's mouse will give you his new invention, the Eraser Eraser. Make sure you use the Instant Revitalizing device and save before continuing on to the Stonehenge Base. When you are ready, head north to those strange stones and down the hole in the middle of them.