Ryouta Sakamoto, an unemployed 22-year-old and top-ranked player of the online combat game Btooom!, wakes up on a tropical island with a bag of explosive devices called BIMs and no memory of how he arrived. He quickly learns that someone in each player's life nominated them for this real-life death game, where seven kills earn a ticket home. Teaming up with Himiko, another stranded Btooom! player, Ryouta fights to survive while unraveling who sent him to the island.