Thonky.com's Pokémon Legends: Z-A Walkthrough

Hérup has a business venture in mind and he leaves the sewer door open for you to meet him.

How to Start the Mission

Go into Wild Zone 5 and go to the northwest corner of the area. If there are piles of sludge, have a Pokémon use Water-type attacks on the sludge to wash it away, then go down the stairs beyond where the sludge was. Follow the path (beware of the alpha Whirlipede) and go through the southeast exit of Wild Zone 5 to find Hérup. Talk to him to start the mission.

How to Complete the Mission

Go into the sewer entrance. When the path splits, turn left, get the Ultra Ball from the ledge, and jump down the ledge and keep following the path. Turn right when you can. At the fork in the path, turn right and talk to Hérup at the end of the path. You will battle him.

Hérup the Collector has a level 46 Camerupt. You get 2208 Pokédollars for winning.

Mission Rewards

You get 4500 Pokédollars, 1x Fire Stone, and 1x Charcoal.

How to Leave the Sewers Quickly

Use the map to go to the Sewer Entrance, then turn around and go up the ladder to go back to the city.