S1·E43 Poseidon Advance, Generator Gavas

While working on her manga, Nagi gets the idea that, instead of chasing after Hayate to further their relationship, she must give him the cold shoulder and force him to chase her. A convenient invitation from Sakuya to a cruise on a familiar-looking ship gives her the perfect opportunity to set this plan into motion. As Hayate wanders around amazed, she shuns him over and over, culminating in the command to "explore the ship yourself". The ship is then threatened by a trio of terrorists, who are handily defeated by the Sanzen'in and Aizawa butlers; however, one of them sets off a bomb, blowing a hole in a cargo hold Hayate had just wandered into. There, he meets Isumi, who had become lost, in danger from a pair of large sharks. As the ship-goers are evacuating, Nagi remarks that Hayate hasn't shown up yet, and goes to search for him. She finds him holding off a shark; as she dives into the water to help, she is attacked by the other shark. Hayate defeats the sharks to save Nagi, but falls unconscious from the combination of the cold water and wounds he received from the earlier explosion. He is saved by Klaus, but Klaus' attitude causes Nagi to worry, as it has the effect she was trying to achieve herself.