It all starts when Bubbie and K'nuckles tell Flapjack that they have to leave for low tides day [because Bubbie needs water to live and low tides day includes the tide being so low the ocean floor is visible and K'nuckles despises the holiday], but Bubbie decides to let K'nuckles stay with Flapjack. K'nuckles runs all over town, pushing down Doctor Barber, a bystander, and Peppermint Larry (even though Peppermint Larry was not in his way), until he reaches a box which is actually, his hiding place he only uses to escape the holiday however,the box was taken. K'nuckles tells Flapjack why he hates low tides day because he was bad and bad people would be punished by being put in a sack and thrown around by mermen and since the two don't want that to happen they look all over town for a hiding place. Unfortunately, all possible hiding places were occupied, so Flapjack suggests that K'nuckles do something good. So, he tries first by apologizing to Peppermint Larry for previously pushing down his ladder, but he fails. As soon as they hear that Ms Leadings class cannot perform the school play because two of the cast members are sick, they decide this would be the good thing for K'nuckles to do. Flapjack plays the role of Poseidon, while K'nuckles plays the part of the quiet boy. All goes well, until K'nuckles learns that his character has been bad and he is to be sacked by the mermen, causing him to suffer a meltdown and attack the cast members. At night, Poseidon [god of the sea] delivers the presents in the people of Stormalong's boots [like stockings] but delivers nothing for the bad people. In the morning, K'nuckles finds nothing in his boot and five mermen right behind him with a sack, Flapjack notices that K'nuckles' boot has a hole which his "present" must have fallen through so he grabs K'nuckles and they fall off the dock on the ocean floor. The mermen follow them but since they can't move fast on dry land, they tie their tails together and form a human shape; two mermen were the arms, two were the legs, and one was the head and body. K'nuckles runs away from the merman monster while Flapjack searches for K'nuckles' present but since the presents for low tides day were not labeled, Flapjack coud not tell which is the right present. So, he takes as many presents in the sack the mermen were going use for K'nuckles [good thing for the mermen is that they had a spare]. Flapjack sees that Poseidon is holding the wave back so he asks him to keep the wave back so Poseidon does. K'nuckles sees Bubbie washed up on the ocean floor but does not care and climbs the wall of water [when the tide is held back it is solid]. When K'nuckles climbs on the wall, water splashes on Bubbie so K'nuckles decides to help by spraying some water on Bubbie to save her life [with help from the mermen who still was going to sack him] when a loud cry was heard and the rest of the people who live in Stormalong standed up to the merman and tied them up when the townspeople was going to sack them, Poseidon put his hand between them and said to the mermen that they should not sack people and sacks will be for your primary presents delivered by Peppermint Larry and your secondary presents will be from Poseidon which will be in boots.The rule for good people who will receive presents has been changed to anyone will receive a present even if they have been bad.