There is a legend that two types of living things exist in the inaccessible deep sea, which are numerous Gulu and few Guta. Gulu has a great reproductive capacity and Guta has parasitic and digestive ability. The number of Gulu is under the control of Guta. Gulu which is digested and absorbed become the fertilizer to nourish lots of plankton in deep sea. No one knows since when, some Guta mutated and started to absorb Gulu crazily. Gulu is not digested any more and change into new Guta. Then octopus Paul step forward bravely to defend submarine order.