105 Goushitsu no Inu  

Dog Room 105, The Dog of Room No. 105, 105 Goushitsuji no Inu, 105号室の犬

In his youth, Takeshi made a vow to assist a girl he had feelings for in his calligraphy class. He has remained loyal to her ever since. Mako views Takeshi as adorable, like a foolish puppy. Along with their mutual friend Honda and other common tropes found in school romances, this story unfolds.