Hayate, Nagi, and Maria go to Mykonos Island for their golden week trip. Hayate asks Nagi to come outside but she refuses. This makes Hayate sad. Nagi knows it's her fault so she decides to go out in the end.
While walking through the streets, the wind suddenly picks up and blows Nagi's hat off. Hayate jumps up to catch it and lands back in the street. But when he turns around he sees that Nagi is much shorter. Has Nagi become younger? Has Nagi shrunk in size? Or has Hayate traveled back in time?