Three years ago, a Hero sealed a Hell Gate. The seal has been weakening ever since, sporadically letting monsters through. After a big group of monsters entered the country through that Hell Gate, the profession of Heroes was needed again.
Touka Scott, a small radish farmer in the southern town of Cheza, is prepared for sudden monster attacks. He built himself a hidden bamboo-spiked pit trap to lure unsuspecting monsters in if they ever try to attack the village. When a monster attacks, Touka tries to lure it into the trap with freshly roasted bacon, but the monster dislikes that type of meat. Thankfully, the Hero arrives to save the village from the monster in the nick of time. The hungry Hero tries to grab a bite of the bacon after vanquishing the monster, only to stumble into Touka's pit trap and die.
After causing the Hero's death, a necromancer from the Hero's old party transfers Touka's spirit into the Hero's body and forces him to impersonate the Hero as the Hero's body is the only one that can use the holy sword to seal the Hell Gate.