After years of fruitless war between the four realms of Gamindustri (Planeptune, Lastation, Lowee and Leanbox) over Share energy, the source of their strength based on how much their people have faith in their goddesses, the four CPUs that rule over them have finally signed a friendship treaty. The treaty bans any attempt at claiming Share energy through military force, in hopes of bringing peace and prosperity to their worlds. Yet, a month after the treaty, Neptune, the CPU Goddess of Planeptune, spends her time goofing off and playing games rather than doing her job, leaving her land's Shares plummeting. Choujigen Game Neptune The Animation follows Neptune and her friends' attempts at raising Shares, while dealing with an external threat that could spell the end of both the Goddesses and Gamindustri itself...

While searching for a run-away cat the twins Riko and Rimu Mikogami find a strange device that transforms them into "Kirumin." It also enables them to turn into real animals. Their older sister Nagisa soon joins them. Now the three have cute, funny and sometimes dangerous adventures.

In the kingdom of Forland, a coup d'etat occurs which leads to the death of the King. In the last moments of his life, the King sends his second child, Princess Alita Forland to escape. Unfortunately, while fleeing, a life and death situation between Alita and the bloodthirsty bounty hunter Falis causes the two of them to switch bodies. Desperate for the safety of her Kingdom, Alita begs Falis to return and protect the Kingdom, offering herself as collateral. After a swift beating on the rebel forces, Falis resumes the title of Princess of Forland, leading to the birth of the most savage princess in their land, the "Murder Princess."

As the mermaid princess of the North Pacific (one of the seven mermaid kingdoms), Lucia entrusts a magical pearl to a boy who falls overboard a ship one night. Lucia must travel to the human world to reclaim her pearl and protect the mermaid kingdoms. Using the power of music Lucia is able to protect herself and the mermaid kingdoms from a growing evil force.