The boy who Hayate meets is revealed to be Wataru Tachibana, Nagi's fiancé. However, Nagi and Wataru can't stand each other.
So, there are bullet trains 
running underground in Tokyo?
¿Y el tren bala también 
va por debajo de Tokio?
Os trens-bala também andam 
por baixo de Tóquio?