Earth collapsed due to environmental destruction, and non-human aliens from the planet Terras descended. UFOs pierced the hazy air, landing one by one. The Terrasians ruthlessly captured 500,000 living humans.

These humans were taken to laboratories for breeding, and as human research concluded over time, they were sold for various purposes: pets, ornaments, and even food.

Nearly 300 years after humans began living alongside Terrasians...

Guest, who had known nothing but the breeding farms since birth, was selected as a pet human for a Human Random Box.

Before long, an order comes in. Inside a delivery box with air holes, Guest waits for a new master.

However,

"Sigh... I ordered this by mistake. Is there really no refund?"

A male Terrasian in a palace-like home groans as he lifts the box containing the accidentally ordered Guest.

"Damn, this was expensive."

He pays the delivery driver with a look of disapproval and carries the box inside.