LG Refrigerator

Hi everyone, I’ve recently moved into a new home, and we inherited a refrigerator with it as well.

It is an LG LMX25964ST model.
The valve that feeds the fridge water was turned off I discovered, but after turning on the valve, water started to pour out of the side door where the ice-maker and the water dispenser is located.

I opened up the side cover, and noticed this…
https://imgur.com/gallery/cHhVr

I’m not sure what that plastic thing is; or how to get a new one.

Any suggestions?