Robert, an adventurer, is looking for the legendary "luminous ship." When Kakeru and the others come upon Robert, he tells them of a certain legend. Long ago, a young man, whose lover had been taken away on a dark ship, went to save her in a luminous one. Only the luminous ship can find the dark one on the dark river. And now, Emperor Gross has the dark ship, and he is going to force Kakeru`s father Haruhiko on board!