[Source of Power: Tits] A fantasy romance about a vampire who can't suck blood and a cow beast-girl. The vampires, who once threatened the lives of people, are now being monitored and managed by the church. One day, Bell, a beastgirl cow, is partenered with Yuki, a vampire who can't drink blood. Since Yuki can't drink blood as source of nourishment, he is so weak that he can't defeat monsters. However, in a desperate situation, he asks Bell for milk...! Instead of blood, breast milk. An unconventional breastfeeding smut begins!