Article: Use your new shrinking ability and walk through the keyhole. Keep going through the keyhole until you arrive at the exit. You'll see a glowing mushroom. You'll notice you're back at the platform before you jumped down to the Drink Me potion (where you got the 4th memory). You can see the next keyhole from the top of the mushroom jump. Approach from the right angle and land on the ledge with the keyhole. It will have arrows pointing to it. The keyhole will bend to the left a little. Keep walking until you get to the exit. At the bottom of the ledges, you will see another keyhole in a corner. Shrink down to see the arrows pointing to it. You'll see some stacked-up blocks. You will need to shrink again to pass through them. Once you pass underneath, you will find yourself in a chamber with plants on the ground. Continue around, past the glowing mushroom in the ground. Behind the rock with the moss on top, you will see the fifth memory. Grab it.

What is a summary?
Go through the keyhole. Jump on the glowing mushroom to boost you up. Find the next keyhole. Go through this keyhole. Jump down the ledges. Keep walking through the hole until you find the exit. Find the memory.