Jack hears tales about a race of amphibians living in an underwater city who have a time machine. He searches them out, and they agree to let him use the machine, but the creatures have not been entirely truthful. In fact they betray Jack to Aku in return for his promise to resurrect their sunken city. When Aku betrays them they first turn all their weapons against Aku, but that proves ineffective. They rescue Jack who uses his sword to drive Aku off – in return, all he asks is that they give him a large supply of fresh raw fish.