The protagonist Nakuto, has his sights on becoming the "War God" aka the Champion of a gladiator-style tournament with a twist. When Nakuto tries to enter this tournament, he learns that there's a special condition required for entering. He must partner with a beautiful woman along as collateral, and so by chance, he finds his childhood friend, Hazumi in town worried for him. Since he has no other choice he enters Hazumi as his partner. Much to Nakuto and Harumi's horror, they learn of the reason for the female partners. Winners of these tournament matches can do whatever they so please to the losing opponent's partner for a whole day.

Tsuyoshi wakes up with no memories in an alley in a town called Shibuya - a world somewhat different from reality. There he meets Ema, the only person who knows him, and who possesses a mysterious power to oppose the world of Shibuya. The two 15-year-olds fight a desperate battle for survival in this virtual world!

Fifteen years ago, a set of twins--a girl and a boy--was born to the king of Linevan. Shortly after their birth, a prophecy foretold that when the girl turned 16, she would bring about the end of humanity. To avoid this terrible fate, the king ordered the princess disposed of...scrapped! She miraculously survived and was raised away from the kingdom that would kill her. But now she has turned 15, and the king's guards have caught wind that she's still alive...and they set out to finish the job! (Source: TOKYOPOP)