Teen assassin Suzume is coming to terms with her past thanks to her new friend Dawn, a grim reaper. Now Suzume just has to deal with her present—helping Dawn fight the Joyless (violent spirits created by creatures dying troubled deaths), trying to be a bit more "normal" (with advice from the free-wheeling Sora) and keeping up with school. But when your first reaction at seeing someone is to judge how quickly you could kill them, how normal can you become? Perhaps the long-absent Professor Steamhead can help. He's brought back a miracle energy source that may save the world, but can Suzume also be saved...by STEAM?!