A peculiar request from an unexpected acquaintance pressures Hachiman into joining her part-time gig. Unbeknownst to him, however, the girl's true intentions may be far more profound and convoluted than he might have anticipated.

Valentine's Day - a day of love, pink, and chocolates. In the spirit of the coming holiday, Hiratsuka-sensei gives her Modern Japanese periods an assignment: write a love letter. So naturally, Hikigaya writes a love letter to the person he loves the most.