Story : After finally making her long awaited smartphone debut, Kaguya restlessly contemplates over how to respond to Shirogane's LINE message. As Hayasaka watches over, she realizes that Kaguya is not aware of the "read receipt" function. If Kaguya lies by responding that she just read the message, she runs the risk of exposing the truth that she had been obsessively staring at Shirogane's message with glee. Weighing out her options to best serve her mistress, Hayasaka decides to explain LINE's functions when suddenly a new problem emerges.