In a world plagued by mysterious machines known as "Tremble," humans are forced to defend themselves by destroying these enigmatic entities. However, a select few have learned to harness the power of the Tremble, using them to their advantage as "Breeder" tamer warriors. These extraordinary individuals must live a life on the run, shunned by a fearful public and hunted by those who view them as outcasts. Undeterred, Ion chooses to follow in his father's footsteps and become a Breeder, dedicating himself to mastering the art of taming the elusive Tremble.