itch.io

There's a secret entrance right above the plant (Just mash your head into the nearby walls and corners until you find it) and you can place some fairy dust, then just speak to the woman and give her an offering. (I just do angel milk but any would do)

You can use Wiki to help you, but its easy once you do it, Scrumptious Banana gave you direction for first half of it, but second half is little complicated, you need play a game which will teleport you to void, just say no or yes, then gift the fairy queen something rare like your cheese or cheese [which can be found after you refined milk in refinery, to buy refinery you need to get to upper new ark], and then fairy tells you how to remove the Giant plant in your way temporarily [you have to do like a quest to remove the giant plant permanently.]