From Renta!:

Office worker Kida loves his private time and prefers silence to socializing. But one day, the previously empty seat next to him is filled by salesman Takamura, turning his peaceful days upside-down! Takamura drags him out to eat lunch every day and chats with him constantly. Plus, it turns out they live in the same company apartment block, and ever since then, Takamura won't stop barging into Kida's place...! Kida would never have taken this lying down before, but Takamura has him strangely charmed... But why...? A puppy-like playboy meets a serious, socially awkward introvert... More...

From Renta!:

Office worker Kida loves his private time and prefers silence to socializing. But one day, the previously empty seat next to him is filled by salesman Takamura, turning his peaceful days upside-down! Takamura drags him out to eat lunch every day and chats with him constantly. Plus, it turns out they live in the same company apartment block, and ever since then, Takamura won't stop barging into Kida's place...! Kida would never have taken this lying down before, but Takamura has him strangely charmed... But why...? A puppy-like playboy meets a serious, socially awkward introvert in this tortured, bittersweet office romance! Less...