There once was an old man who lived in a hut that sat snugly underneath a bridge, on the bank of a river. The river was large, artificial, and cut through the middle of a strange city. Ominously above the center of the city, there hovered a colossal monolith that reached beyond the clouds. Every week the monolith excreted half a million metric tons of trash and debris into the river, and that was what the old man subsided off.

He was a non-entity, a person with no name, titles or deeds. Every day he just caught fish and salvaged junk from the river. He ate the fish, and used the junk to maintain his tools and hut. He also collected items that were of interest to him. The odd broken watch, obscure toy or anything in between. His hut was filled with such artifacts.

Most recently, he fished up a boot. Inside the boot was a small box, inside the box was a purple potion, a mysterious seed, and some hand written instructions. They read: 

Fill the boot with soil. Plant the seed three inches deep. Add one drop of purple liquid. Continue adding the purple liquid, one drop a week. No need to water. Keep away from sunlight.

The old man followed those instructions exactly. He gathered the dirt from a nearby park and kept the boot away from moisture and light at all times. Once a week he would add a drop of the strange purple liquid. It faintly glowed when coming in contact with the soil, before slowly oozing downwards.