This is an action-adventure game released by Bothtec in 1986. The main character is drifting as a spirit in the ruins that suddenly appear from under the sea. There is no explanation as to why he has become a spirit or what he has to do, but by exploring the ruins, the situation becomes dimly apparent. One of the highlights of this game is the spirit ride system, in which the player possesses a defeated opponent. The attack methods and durability vary depending on the possessed body, so the key to the strategy is which creature you possess as you continue your search. In addition, the items that can be obtained change depending on the player's actions, and the storyline and ending change, so it is up to the player to decide how to proceed with the exploration of the ruins. The ability to experiment with this and that is a unique aspect of this game. The cinematic elements of the game, such as the rich sci-fi character designs, the profound movements of the humanoid characters, and the effective sound of the waves, will add to the excitement of the game. The opening and ending music was composed by Crystal King, which was a big hit at the time.