Godzilla, Rodan, Mothra and Anguirus explored the sewers and got lost, they tried to find a way out but it’s been hours, and it seems like they were never going to get out, every few minutes they toke a break

Rodan: Great! Now we’re lost because of you Godzilla!

Anguirus: Hey, it’s not entirely his fault, stop blaming others for your mistakes.

Godzilla and Mothra glance around, possibly looking for an exit and get out of the filthy tunnels of the sewers, until they heard a roar..there was something in there with them..