From Good Girls Scan BL:

One day, the overworked researcher Koki discovers a “dog” lying unconscious at the foot of his apartment complex and decides to bring it home. The next day, Koki wakes up to an unknown man in his apartment! Is he a burglar?! Amidst Koki’s panic, the man transforms into the “dog” he found last night and starts talking…! “Koki, I’m the dog you saved! Thank you, you’re really kind!” Thus starts the duo’s life in the shared apartment as pet(?) and owner…?! A loving story about the lives of a handsome human-transforming dog and a fussy scientist under one roof!