This is book number 11 in the Goblin Slayer (Light Novel) series.
HE DOES NOT LET ANYONE ROLL THE DICE. Summer is here, and Female Merchant pays Goblin Slayer and his party an unexpected visit at their usual tavern to make them a proposal. Her next trade route will take her through the vast eastern desert where goblins now run rampant, and she would like the party to escort her. They accept her request, and the group promptly sets out for the arid eastern borderlands with its different cultures, vicious traps, harsh climate, and shadowy desert figures. How will our heroes fare in this unforgiving foreign territory...?