Can't get into slimy sub boss

[Bigkoala3]

I have tried numerous times after beating the game to get into the slimy sub boss treasure room for the stone with the message the door can't open popping up. How do I get summoning stone #2?

[Asakura Shinichi]

You can only see the summoning stones when you play as male and have the alchemist costume equiped, i think you need to find 4 stones.
You can find the summoning stone locations in this topic
https://steamcommunity.com/app/1748620/discussions/0/5971271658121176646/

[Phlebiac]

Początkowo opublikowane przez Asakura Shinichi:

You can only see the summoning stones when you play as male and have the alchemist costume equiped, i think you need to find 4 stones.
You can find the summoning stone locations in this topic
https://steamcommunity.com/app/1748620/discussions/0/5971271658121176646/

3 stones are required :)

[Asakura Shinichi]

Początkowo opublikowane przez Phlebiac:

Początkowo opublikowane przez Asakura Shinichi:

You can only see the summoning stones when you play as male and have the alchemist costume equiped, i think you need to find 4 stones.
You can find the summoning stone locations in this topic
https://steamcommunity.com/app/1748620/discussions/0/5971271658121176646/

3 stones are required :)

Probably, beaten the game 2 weeks ago or so, hard to remember how many summoning stone there were to find.