Atlantis 2: The Mysterious Crystal

The story takes place after Milo and Kida stayed in Atlantis. Several cargo ships were attacked while passing through the sea north of Atlantis, so Milo and Kida followed the visiting expedition team to investigate, only to find that the attackers were not robot lobsters, but other mysterious forces. After overcoming this crisis, Kida embarked on a journey with Milo and the expedition team to find out the most suitable way to arrange the magic crystal. She wanted to find out why her father wanted to hide the crystal and nearly destroy their civilization. They also have to make a decision, should they use the magic crystal? Or hide it forever?