In the café where Tsumugi works, there is a customer she is concerned about. A lady who seems to be an office worker, who orders bitter black coffee every day. "Isn't it bad for her health to consume that much caffeine every day...?" Thinking that, Tsumugi one day... A heartwarming slice-of-life yuri, part of a series. * This work is the e-book version of a personal publication by Ayu Inui. 【34 pages】