The Zersetzen Forest is a one-shot that is completely homebrewed. It is a great way to introduce beginner players to the game of D&D. I wrote it to be played with three 3rd level characters, but you can always tweak the CR of the monsters.
In this adventure, our adventurers had met during a prior mission and have been sent to Dusseldorf, a modest town near the Zersetzen Forest. There have been rumors about a dark evil corrupting the forest from within. Our adventurers begin the story waking up midday at a local inn. They have to get more information about the dangers that await them, gather supplies, and enter the forest. But it isn't the animals or beasts of the forest they have to worry about. It's the foliage and plant life that's been corrupted by a dark and menacing being at the center of the forest. Botanists beware!