Akira Tsubaki, a typical high school student, finds himself seated next to the enigmatic Mikoto Urabe, a peculiar transfer student with a tendency to doze off in class and laugh unexpectedly. Despite her aloof nature, Tsubaki's curiosity is piqued one day when he discovers Urabe napping at her desk and, on a whim, tastes her drool left behind. This impulsive act leads to Tsubaki falling ill, only to be visited by Urabe who diagnoses his condition as lovesickness induced by her saliva. Thus begins their unusual bond, where Urabe shares her drool with Tsubaki daily to keep him healthy and connected.