Geo and Sonia discuss recent events when they meet the UMA Plesio. Plesio has been trying to protect the lake from intruders and pollution, and he had attacked Mega Man in error. However, Rich commands a group of workers to begin filling in the lake, enraging Plesio Surf and causing him to attack them. Mega Man and Lyra Note intervene, giving Rich the opportunity to submerge to the lake's bottom and steal the OOPart (The Rock of Saurian) hidden below.