Natsu no Hatsujou, Kimi to Seishoku

Hinami is a high school girl who suddenly develops a mysterious disease called "Kissy." This strange condition causes numbers to appear on her wrist, and when the number is odd, she enters a state of heat, losing control of her urges. She tries to hide her illness from her boyfriend, Sawano, but the situation becomes impossible to conceal when she unexpectedly goes into heat during class.

As Hinami struggles to manage her condition, her relationship with Sawano is put to the test. The disease forces her into increasingly compromising situations, blurring the line between her desires and her daily life. With no cure in sight, Hinami must navigate the consequences of Kissy while keeping her secret from those around her.