Robby and Hatchi visit Hamama II, home of the Great Eel Festival. Little do they know that Yang and his gang have tracked them there, where they are also enjoying the festivities, as Yang is affected by the eels' legendary powers of virility.

Low on fuel, Robby and Hatchi find themselves on Mulberry 8, a world where mechanical people are in charge and living beings are slaves. The two must learn to navigate the feudalistic society and adapt to anti-human discrimination.