From the back of the box:
Let's go Goemon!
A giant UFO has appeared over Oedo Castle, and the Mystical Ninja is off to save the world again! Control Goemon and his giant robot, Impact, Ebisimaru, a truly twisted ninja, Yae, the part-time militant mermaid, and Sasuke, a mechanical warrior. This brave band must travel from town to town, collecting information and purchasing helpful items in their quest to defeat the dreaded Peach Mountain Shoguns.
Power up each character's weapons and learn their unique special moves and magical transformations to take on determined enemies and overcome challenging puzzles. The future is in your hands, Goemon - don't blow it!