Prontera Culvert starts with Recruiter in Inside Prontera (88, 105). The steps below are read from the quest's script on this server, in the order the script's quest stage moves through them.
Walkthrough

1 Talk to Recruiter in Inside Prontera (88, 105)
When Script check: not MISC_QUEST & 8 Choose “Volunteer.” You get 3 ×
Red Potion; 1 ×
Milk; 1 ×
Orange PotionThen Sends you to Prontera Field (274, 208) ...to give you hope.
Are you ready, hero?
I will now warp you
to the Culvert.
Script:
npc/quests/quests_prontera.txt:125· MISC_QUEST = MISC_QUEST | 8
2 Talk to Recruiter in Inside Prontera (88, 105)
When Script check: not MISC_QUEST & 8 Choose “Situation...?” then “Volunteer.” You get 3 ×
Red Potion; 1 ×
Milk; 1 ×
Orange PotionThen Sends you to Prontera Field (274, 208) ...to give you hope.
Adventurer...
I will now warp you
to the Prontera Culvert.
Script:
npc/quests/quests_prontera.txt:125· MISC_QUEST = MISC_QUEST | 8
3 Talk to Recruiter in Inside Prontera (88, 105)
When Script check: not MISC_QUEST & 8 You get 3 ×
Red Potion; 1 ×
Milk; 1 ×
Orange PotionI would like to thank you for volunteering to do your part for our great kingdom. Here, take these provisions for your battles against the forces of darkness.
3 Red Potions, 1 Milk,
and 1 Orange Potion
...to give you hope.
Script:
npc/quests/quests_prontera.txt:125· MISC_QUEST = MISC_QUEST | 8
Rewards over the whole quest
3 ×
Red Potion; 1 ×
Milk; 1 ×
Orange Potion
How this page is made: every step comes from the NPC scripts the server loads for Episode 13.2 (the file and line are under each step). "When" lists the checks the script makes before that branch runs; "Have with you" are the items it counts; experience from getexp is multiplied by the server's 50x quest rate. NPC lines are the script's own text.