One sleepless night, Kou slips out to walk the streets. Life after dark is a revelation! When flirtatious Nazuna invites Kou to spend the night at her place in an abandoned building, he's stoked! But then he awakens to kisses on his neck with a little too much bite to them... Is it just the delicious taste of his blood that makes her meet him night after night for late-night adventures, conversation and...naps? Or something else? Then, when a cute girl from Kou's past shows up and competes for his attention, his budding relationship with the undead is put to the test!