The story is set on a parallel Earth where humans and the Eniso, a humanoid species with animalistic features, live peacefully together. The Eniso possess various animalistic appearances. However, this balance is shattered when alien beings invade Earth.

These aliens are described as a powerful insectoid race, or perhaps a deeper form of AI-driven inorganic life. Their goal is to mine rare metallic energy hidden beneath ancient Earth ruins. The aliens discover that humans, possessing "faith," can absorb this energy. Therefore, they dismantle Earth's defenses and begin abducting humans to work as miners, forcing them to use their faith to summon Losi metal. Enslaved humans eventually die, but the aliens seem to harbor a particular hatred for them. Losi metal is a rare energy source that can also be used to forge more powerful weapons.

The surviving Eniso, lacking faith, escape this fate. To prevent Earth's resources from being depleted, they piloted the GA-JUN mechs, co-developed with humans, and formed the Animal Earth Defense Force to fight against aliens. After years of fierce warfare, the Eniso people split into two factions: "Balancing Life (Protecting Humanity)" and "All-Out Resistance (Abandoning Humanity)."

The story's protagonist is Ina, a red panda pilot played by the player. She joins the "Balancing Life, Protecting Humanity" defense force to find her missing father, who is the original designer of the combat mech GA-JUN.

Ina, now a key member of the defense force and known as "Sloth," unexpectedly loses her memory during a mission. Her GA-JUN mech, in protecting her, suffers damage to its memory core. This causes Ina's memory compatibility with the mech's AI to gradually decrease, and the mech's weaponry becomes increasingly unusable. After basic training, the mech AI GA-JUN assists Ina in gradually unlocking basic combat functions. Before his memory core was damaged, GA-JUN told Ina that she needed to find companions to regain her and GA-JUN's memories, and that the truth she was searching for was still unclear, so she shouldn't believe the illusions before her...

Key Features:

(1) Mech theme combined with survivor gameplay, allowing for the creation of more powerful weaponry.

(2) Animal pilots possess unique skills, each with distinctive abilities to utilize.

(3) Mech assembly and painting, incorporating elements beloved by mech enthusiasts.

(4) An animal-saving worldview, rescuing talkative humans and saving the Earth.