What is "I saw something like a gun underwater"? How to get it?

Task name: the arm at the bottom of the lake

Special conditions: one day after the giant starfish breaks,

Reward: Experience value: 2500 popularity: 5

Reward: 50** wrist guns.

Process: 1. Morobok 1F talks with businessmen.

2. Story Notes on Going to the Ruins in Northeast China 1

3. Salvage the villain's arm in the north of Morobok, and then go back to fight. Don't forget to take something.

Talk to the couple and send them to the camp in the south.

Remarks: 1. It seems that you can start directly, but there is no extra reward.

2. Zhou Mu can directly enter the battle with a wrist gun.