Winter Morgan 
Madness in the Mine [EPUB ebook] 
An Unofficial Minecrafters Time Travel Adventure, Book 5

For as long as the residents of Meadow Mews can remember the town mine has been emptied of any precious metals. Everyone has a story about why the mine was barren. When Brett and Joe are working on a farm near the mine, they fall into a portal, which leaves them in the past. They are in Meadow Mews before any of their friends lived there and discover the real story behind the mine. They learn about how their town was formed and watch the first library being built in the Minecraft Universe. While in the past, the get caught in the middle of a battle, where everyone has been placed on hardcore. Will they survive and make it home, even though they already in Meadow Mews?