in stranger things quest
The ground is made up of different tiles. Head east, then south, then north where the floor looks Icy. There is another cave. Head through the cave. nothing cave... 1 hour i try cant discover that cave...
any video guide
north of the ice is what looks like a little area with a grating of sorts over what looks like a chasm. on the left side of the top is a row of three wall tiles, the middle one has a cave. if you can't see it, try turning up the brightness on the monitor - it might help.
Don't worry though, that quest is awfully designed. you'll hate the timer later on.