After their parents' deaths, brother and sister Akito and Akiko Himenokouji were forced to live with separate families for six years. But now they have finally reunited and begin to live together. It quickly becomes apparent that Akiko harbors romantic feelings for her brother; however, Akito only sees her as a sibling. When three more girls—Anastasia Nasuhara, Arashi Nikaidou, and Ginbei Haruomi Sawatari—move into their apartment, Akiko's hopes of living alone with her brother vanish. Moreover, these girls also like Akito in one way or another, making it even more difficult for Akiko to gain her brother's undivided attention. As the girls fight over who should take care of Akito, they display various eroticisms that may be a little too much for a normal man to handle. [Written by MAL Rewrite]

The girls are saved ... by none other than Catty Nebulart herself! Now, the race is on as Catty struggles to complete her crowning achievement: a huge machine that will bring life to a lifeless world!

Moments after an atomic bomb falls over Hiroshima, a secret Japanese submarine sails into battle against its American counterpart, and both are lost to history. Some fifty years later, a special UN task force sent to investigate unusual phenomena in Antarctica is threatened by a mysterious black cylinder.

Second season of Time Bokan 24.