Smuggler's Cave

Hi everyone,

I am having a bit of a problem with the guard at the entrance. I was in the cave at a relatively low level, and I had the option to tell the guard I came to buy bloom. I decided to leave and come back later though, as I took a wrong answer right after and the guard kicked my ass.

Now I am a few levels higher and I wanted to go back to explore the cave. However, the option regarding the bloom no longer is there. I suppose I must have gotten the info at some point between my last save and the guard kiling me. However, I can find no book or note that would allow me to learn about the bloom operation. Can anyone tell me where I should look?