Btooom!

Synopsis

Ryouta returns to Kiyoshi with the case of food supplies. In a flashback, Ryouta's mother tried to commit suicide after regretting causing him to "disappear." While Ryouta and Kiyoshi are eating, near the river a corpse washes downstream, which turns out to be a pants-less Mitsuo, leaving Ryouta and Kiyoshi to wonder what happened. Ryouta, suspecting that an enemy may be lurking upstream goes to investigate and discovers Himiko waiting atop a cliff. She then attacks him with a corrosive-BIM, drawing him out into the open. Ryouta tries to reason with her, and it seems to work but when he tries to approach her she attacks him. Realizing she was trying to kill him, Ryouta rushes towards her but she attacks him with her stun gun. Not wanting a repeat of what happened on the cargo plane, Ryouta defends himself causing Himiko to stun herself. While unconscious, Ryouta takes her BIMs and as has a morality moment about stripping her. However he shakes that feeling when he pieces together that she was assaulted by Mitsuo. When Himiko regains consciousness she finds herself being carried back to camp by Ryouta, and mistakenly thinks she would be violated again, activates a hidden timer-BIM in her pocket but Ryouta deactivates it. Back at the camp she explains to Ryouta and Kiyoshi that everyone on the island had been picked by someone they knew to "disappear." Although Kiyoshi offers Himiko to team up with them, she says that there is nothing left for them if they go back. Ryouta realizes that his own family had chosen him for defying them. At the same time, the group is attacked by a pack of komodo dragons

(Source: Wikipedia)