A glittering galaxy awaits inside! If you want treasure, get ready to dig! A retro-colorful dark-pop exploration STG fantasy!

Touhou Houtenkyou ~ Treasure Castle Labyrinth is a fan-made Touhou Project game made using the Touhou Danmakufu ph3sx shooting game engine.

Treasure Castle Labyrinth was first conceptualized as a hypothetical Touhou fangame by Iroboshi of iroirodou around the release of Undefined Fantastic Object, and was later made into a music album in 2014 with the help of Pesot.jp/. Development of the Treasure Castle Labyrinth game began in 2018, spearheaded by DOGSDAY. In 2020, the members of both iroirodou and DOGSDAY came together and established a common circle dedicated to the game's development: UWASA Enterprise.

A strange rumor had very recently spread throughout Gensokyo.

"I found a place where you can get tons of treasure!"

"I went in to look for treasure, but I started seein' things, and I lost all my valuables."

"If you enter that labyrinth, mysterious things will happen..."

...And so on. Nearly everyone was gossiping about a huge labyrinth full of treasure.

Surprisingly enough, this supposed treasure was located somewhere up in Heaven.

Humans shouldn't normally have been able to get into Heaven, but according to those who'd been there, they'd been guided there by a "three-colored lantern".

Reimu, Marisa and Sanae went to search for someone who knew more about the lantern.

The three heroines each found a companion, each with their own objective in mind.

And so, they set out on an adventure in search of the treasure's hiding place.

With lamplight in hand, the six ventured into the labyrinth, which almost seemed to become a glimmering galaxy as soon as one set foot inside...