The "violence gun action" manga's story centers on a dual gun-wielding protagonist who makes a deal with the devil to reap the souls of sinners.

In the manga's story, extra-terrestrial life known as Trench Walkers reveal themselves, emerging from the Antarctic, and walking on the sea floor. Their goal is to terraform the Earth to their liking, which involves raising the sea level by 70 meters, thus rendering Tokyo and many other population centers uninhabitable. They have also begun to change Earth's surface water into what they call Nectar, the "divine water." Those who are incompatible with Nectar have a high chance of death when imbibing it. However, there are girls who are found to be compatible with Nectar, and they are recruited to be marines in a fight against the Trench Walkers, boarding ships to do battle in a new deep sea front line. The story centers on Hiro Todoroki, who receives a message from his older sister, a marine supposedly missing in action. The message tells Hiro to find a formidable marine named Kiriri Tsunoba. Though lost and confused, Hiro heads to the Masakado Girls Academy Submarine Unit with the intent to join them.

18-year-old Koreeda Kazuki is a genius hacker whose only real skill lies with computers. Into his aimless life steps a wealthy man who makes him a proposition he finds impossible to refuse: that he will become Koreeda's investor on the condition that Koreeda use his abilities to help the man "conquer the world." In cyberspace where national borders hold no meaning, thus begins the story of two modern-day adventurers who stand against crime on a global scale.

Muto Yuzuki was ready for a whole new life and a different self when she got to middle school but she didn't expect it to be literally torturous. Yuzuki is “persuaded” by an upper classman named Funaki Aoi to join the Torture Club on campus which has been secretly training students to enter the field of military and police organizations as interrogation experts. Aoi sees something inside Yuzuki and thinks she might be a prodigy in torture methods. Naturally, Yuzuki wants nothing to do with such vulgar conduct but the more she spends time with the club, the more she starts to realize her own dark potential.

Lately in Shibuya, many high school girls have gone missing but that doesn’t stop Yaida Kirin our guitar slinging, Tae Kwon Do wielding High School Ardor of Justice from venturing into the night to save the poor souls in need of help. It’s a simple life for our heroine but little does she know that a mysterious group of people have joined her bid for justice. Then there’s Reido Serujio. What connection does he have with the mysterious group? What is he hiding beneath that weak, timid exterior of his? And why he won’t stop following Kirin-san!? Is it love like Yuki, Kirin’s friend, says?

High school student Jinpachi Kogure is a member of the manga club and is no good with women. Yumika Testuyoshi is a troubled female high school student who's always skipping school and searching for a girl she doesn't hate. However, these two are in reality young masters of the art of killing people: "Young Guns"—-!