Tongari Thanatos

Moroha is a high school student from Chiba who has just moved to the countryside. He struggles to adjust to his new life and is about to give up on all hope of youth and romance, when a mysterious bump suddenly grows on top of his head, which her little sister calls "Thanatos". And it seems Thanatos's appearance is connected to Moroha's attraction to Eriko, the girl who sits next to her in class. But there are a lot of people who will try to stop Moroha from getting close to the girl!