death note starts with your average (but smart) student light yagami who sits in class staring out the window, notices something falling and goes to see what it was after class, and low and behold, it was the death note! which is basically a shinigami (death reapers) tool of killing literally anybody. at first light didnt believe it was real and was just a gag or something, as any body would at first. but then he tested it. he gets lots of ideas and decides he wants to start killing more and more, he wants to be basically the justice of the world to make it a better place for all the good people. but as expected, the authorities dont see eye to eye and they try and use all their resources to find light. through the whole series its always "omg omg omg how is this gonna work" and such. light always blows your mind on the things he does, its a rollar coaster ride from start to finish. one of the most popular series of all time and for a good reason.