While struggling to make friends after his parents’ divorce, Koyomi Takasaki meets Kazune Takigawa, but apparently, they already have. Kazune reveals that she’s from World Line 85, an alternate universe in which she and Koyomi are lovers. But in a reality where moving between dimensions is natural, could Koyomi be the one from another world?
What was with you just now? 
Why are you calling me that?
Warum nennst du mich so?
¿Por qué me llamas así?
¿Por qué me llamas así?
Pourquoi tu m’appelles pas
par mon prénom ?
Ma si può sapere che hai?
 Perché mi chiami così?
Que jeito é esse de falar comigo?
Ты меня специально
по фамилии зовёшь?