Many years ago solitary lifeforms reached to earth.They meet with people on planet.they were dubbed Mecha -ude as when they meet.They have little resemblance with Because they have great friendship Hikaru Amatsuga work hard.
To save Arma the opposite group ARMS assigns the both Mecha -ude user Aki Murasame to follow him whenever he reached.She is also looking for strange snake -type Mecha -ude wielder,who has put many of her companion in a strange state.Moreover a society known as Kagami Group is looking for Trigger Arm.