A young Priestess joins a group of rookie adventurers who decide to raid a cave infested with goblins. Things quickly go awry when the inexperienced party is ambushed by goblins, resulting in all of them save for the Priestess being killed, raped or captured. The Priestess is rescued by the arrival of Goblin Slayer, who swiftly kills the goblins attacking her. She decides to follow Goblin Slayer as he proceeds deeper into the cave, killing more goblins and teaching her about their psychology and battle tactics. With the Priestess' help, Goblin Slayer is able to kill the remaining goblins, including a goblin shaman and hobgoblin. They then discover several goblin infants, which Goblin Slayer mercilessly kills to prevent them from becoming threats in the future. Despite the traumatic experience, the Priestess decides to join Goblin Slayer as his adventuring companion.

The Goblin Slayer is a silver-ranked adventurer covered in armor from head to toe. The Goblin Slayer never accepted any quests from the Adventurers' Guild other than quests to slay goblins so he was perceived as strange by the other guild members. Ever since she was saved by the Goblin Slayer the Priestess had been joining him on quests and slowly began to understand how he functions.

Goblin Slayer and his party go into the sewers of Water Town to investigate some brutal incidents they think were caused by goblins. When they go down to the sewers, they are immediately attacked by a horde of goblins. Because of the sheer number of goblins, the party has a hard time dealing with them all and then a goblin champion also appears before them...

The battle against the Goblin Lord and his horde of goblins had begun, and High Elf Archer, Dwarf Shaman, Lizardman Priest, and the other members from the guild face them head-on. Meanwhile, Goblin Slayer goes to face the Goblin Lord alone...