Violet Evergarden Gaiden: Eien to Jidou Shuki Ningyou

The Drossel royal family pulls strings to have Violet tutor Isabella York, a student at a prestigious girls' school, for her upcoming debut. Isabella may have a well-connected father but as Violet befriends her she discovers the debutante has an unhappy past of poverty and separation. With Benedict's help and with the emotional power of letters Violet sets out to reconnect Isabella with her past.