Who Came Up With the Onomatopoeia 'Kapo~n'? It's Amazing.With summer vacation coming to an end, Nagi is saddened that there won't be any more free time to spend with Hayate. After reading a manga, Nagi decides to take Hayate fishing. As they reached the Sanzenin Lake, Nagi was ready to go fly fishing, but Hayate told her it’s challenging. While Hayate and Nagi are having romantic time fishing (in Nagi's mind) on a boat, the lord of the lake overturns their boat. The both of them saw Maria with the lord from before, in which she was able to catch it. Returning home, Hayate takes a bath and is joined by Tama who breaks the bath's water heater. Hayate becomes depressed because he believes he's always causing problems for Maria and attempts to fix the bath, only for it to be destroyed once again by Tama. But Maria tells him that she likes him as a hard-working. Then he tripped and fell on Maria. Nagi saw Hayate on top of Maria and made her turned one of the fireworks to a bomb launcher and shot Hayate, sending him to the starry skies and exploded like a firework.