Tsubaki Akira, a completely ordinary boy in high school, happens to lick the saliva of a mysterious girl, Urabe Mikoto, who just transferred into his class. The next day, Tsubaki is bed-ridden with a inexplicable fever that won't break. Five days later, Urabe makes an unexpected visit to Tsubaki's room and tells him to lick her saliva, after which his fever immediately breaks. Tsubaki asks Urabe what caused the fever, and she responds that he was lovesick. That marks the beginning of Tsubaki and Urabe's very ordinary yet somewhat odd romance!