Rin Yoshida is the newest student to E-Class. She was adopted by Karasuma when she was ten, but at first she refuses to let anyone know this. She highly skilled in the art of defence and is on her way to becoming a professional assassin though Karasuma wants her to defend like he does. Will she choose his path or keep in her own direction of assassination? Will E-Class change her cold, sarcastic ways or will it make her worse and push her further away? Or will she unexpectedly find love?