Btooom!

Most girls waking up without any memory and meeting a serial killer would panic, but not Rachel. In fact, far from being her biggest problem, killer Zack might just prove a convenient resource when it comes to finding a way out of the building in which they're both trapped!

Yuuya Nomoto was horrified to discover that the vehicle he was driving was being used to kidnap a high school girl, but he's even more shocked when the girl, Hitomi Uzaki, literally tears her kidnappers to pieces instead! Then she forces Yuuya to drive her to an arena where she bets the value of his organs on herself to win in a death match against a half-lion hybrid! Even more astonishing: Hitomi wins! That's because she's a Therianthrope, a genetically engineered fighter created specifically for the underground death matches known as Killing Bites! And now that Yuuya has been pulled into this dark underworld, he has no choice but to continue working for Hitomi. Because who's going to fight against a girl who's part honey badger?

During a summer camp, 15 children, 8 males and 7 females, find a grotto by the sea. Deep within they discover working computers and some electronic equipment, and later the owner, a man called Kokopelli. Kokopelli claimed to be a programmer working on a brand new game, in which a large robot has to defend the Earth against fifteen alien invasions. He persuades the children to test the game and sign a contract. All but one of them signs; barely a moment later they mysteriously awaken on the shore believing what happened was just a dream.

In the near future, a Virtual Reality Massive Multiplayer Online Role-Playing Game (VRMMORPG) called Sword Art Online has been released where players control their avatars with their bodies using a piece of technology called Nerve Gear. One day, players discover they cannot log out, as the game creator is holding them captive unless they reach the 100th floor of the game's tower and defeat the final boss. However, if they die in the game, they die in real life. Their struggle for survival starts now...