Amane's mother, Shihoko, arrives at the apartment without warning while Mahiru is visiting. Amane asks Mahiru to hide, but Shihoko eventually finds her, and the two neighbors frantically try to correct Shihoko's assumption that they are dating. Nonetheless, Mahiru is touched by Shihoko's motherly kindness. After Amane sees how happy Mahiru is to be called by her first name, he tries calling her "Mahiru" too. From that day on, the neighbors call each other by their first names.
I have to catch you off guard to make sure 
you're actually taking care of yourself.
عليّ أن أزورك فجأة لأتأكّد من أنّك
تعتني بنفسك جيّداً
Ich will ja sehen, ob du anständig lebst,
das geht halt nur unangemeldet.
¿Cómo voy a saber si te cuidas?
Debo esperar a que bajes la guardia.
¿Cómo voy a saber si te cuidas?
Debo esperar a que bajes la guardia.
C’était le seul moyen de vérifier
que tu vis sainement.
Ma così non potrei rendermi conto 
del tuo stile di vita, non ti pare?
Como vou te pegar aprontando
se eu não vier de surpresa?
Если предупрежу, то не смогу проверить,
следишь ли ты за собой.