My Life as Inukai-san's Dog.

On a rainy afternoon, a male high school student comes to shivering on the street with no memory of how he ended up there. He’s soon found by his classmate—and crush—Karen Inukai, who brings him back to her home. Still dazed by the situation, he’s stunned when she begins to undress and seems ready to bathe with him, leaving him completely confused.

The truth hits when he catches his reflection: he’s been turned into a dog. Inukai takes the puppy in, names him Pochita, and he’s forced to navigate daily life on four legs while searching for a way out of his bizarre predicament. As he plots an escape, he also starts seeing a side of Inukai that never showed itself at school.