What do you do if one of the girls in your class is both your best friend and secretly an assassin? And if another girl you know says she's a ninja, and your life is constantly being threatened by other ninjas, hired killers and redheads with mysterious personal vendettas? If you're Yasuna Oribe, the answer is that you do very little and go on as if as everything is normal, even when the weirdness expands to include escaped bears and killer mosquitos. However, that's not because Yasuna is incredibly cool and blasé about danger, but more because she might be a few tiles short of a full mahjong set. If it seems like Yasuna's path through higher education will lead to a premature grave... you just might be right as things get a little crazy in KILL ME BABY!