Haruki hears about Kazusa's moving from her mother, who she hadn't been on good terms with.  He feels betrayed and angrily confronts her.  But his words force open the door to Kazusa's heart, which she had desperately tried to keep closed so that the three of them could stay together.
You need to lie down.
Du musst dich ins Bett legen.
Deberías descansar.
Deberías descansar.
Tu devrais aller te coucher.
É melhor se deitar.