Ash and company are about to arrive in Sinnoh via ferry line. The trip is smooth-sailing. Ash and Pikachu take this time to relax and glance again on the beloved region.
"Well, there it is, Pikachu," Ash remarks. "Sinnoh region once again. It seems it never changed when we last left."
"Pika! Pika!" Pikachu utters.
"I sure could count on revisiting old pals there. But I am prepared for what is about to happen." Ash then turns back to the cabin when a thought enters him. "Right, where are my pals?"
Speaking of which, the first timers use this time to embrace the new culture from a new region.
Mallow and Lana glance over the beautiful Pokémon (an Eevee, a Buneary and a Skitty) that are to be presented for Pokémon contests.
"Look at those neat Pokémon! They look so…pretty!" Mallow reacts.
"I could almost hug them!" Lana squeals.
Sophocles, meanwhile, is entertained on browsing about Sinnoh Pokémon from an Internet booth in the ship. "This is so cool! A lot of Pokémon! A lot of Pokémon types! So much info that it would take me a week to get through everything!"
Finally, Kiawe checks out the workout gym onboard where he spots a boxing ring that has a Machoke and a Hitmonlee sparring each other. "This is cool. Fighting Pokémon, training with each other. I am…I am entirely speechless."
Ash somehow enters the gym in search of his companions, and spots Kiawe in the midst of an engaged crowd. "Kiawe, I've been looking all over you guys."
"Sorry Ash," Kiawe replies. "I just got curious of this ferry's amenities. I didn't they have built-in training gyms in here."
"I know too," Ash responds. "We're about to land. Where are the rest?"
"They must have wandered around," Kiawe answers. "You told us Ash that we could have fun around the ship."
"Well, I must have taken it too literally."
"We could always huddle to our cabins."
"Good idea. The captain always gives instructions when landing."
As the ferry approaches the port area, the captain of the ship gives the announcement, "Good morning, passengers, ladies and gentlemen, we are expected to arrive at the port for thirty minutes. So please prepare your belongings, clear all establishments and line up for landing. As always, thank you for taking this trip and welcome to the Sinnoh region."
As such, the passengers prepare their belongings and vacate the cabins to form a queue upon entry to the Sinnoh region. Ash and Kiawe are able to prepare the stuff. Eventually, Mallow, Lana, Sophocles and Lillie meet up with the guys.
"There you are! We've been looking all over the ship for you!" Mallow exclaims as they slow down their breaths after they went in a hurry.
"Well, I was looking all over for you guys around the ship a while ago," Ash replies.
"Is that so?" Sophocles utters. "Sorry, we got so overwhelmed. There are just so many in this region that we want to see."
"Don't worry about it," Ash assures. "There's plenty to see in the Sinnoh region."
The ship then arrives in the port. The passengers safely get off the ship and go to their respective destinations. Ash and friends take a shuttle that is designated specifically for participants and visitors for the Equinox Cup.
Along the way, the newcomers are mesmerized on the mountainous sights of the Sinnoh region. The shuttle traverses on a cliff-side road with a view of the vast ocean. Thus, it is awe for them to see such a view with wild Pokémon roaming around their sights.
Ash looks down to the ocean to see another ferry approaching the port.
On that ferry, Team Rocket happens to stumble upon there in hopes of cornering Ash and the gang. They have yet to realize from some miscalculation that they arrive at the wrong ferry. The team of misfits search around the ship for them, to no avail.
"Where are those infuriating twerps?" Jesse groans at herself.
"Spot any sign of them?" James asks as he enters the picture. But Jesse shows her fist instead.
"We have been circling in this ship for two days in a row. And there is no sign of the twerps and their delectable Pikachu!"
James gets even uneasy with Jesse's demeanor. "I think you used the wrong words. But I get your valid point!"
"Maybe we should consult to the reliable sources," Meowth suggests as he walks by.
"What reliable sources are you referring to?" James asks.
"Like this." Meowth then proudly show the visitors' logbook that he stole.
Jesse then looks upon the book for hopeful evidence for their twerps. "This is a list of passengers. Where did you get this?"
"Let's just say a little distraction went by at the public mess hall. And when the usher left, I 'borrowed' a little something from his post," Meowth brags, with Wobbuffet agreeing.
"Come on! Let's look upon it before they discover the logbook's gone. And who knows who will be searching every one of our bags," James overthinks.
But Jesse violently snaps him out of it, "You are not helping the situation James." She then flips the pages hurriedly until she arrives at the K section for "Ketchum". To her shock, she finds nothing. "What?! The twerp's name is not here!"
"What do you mean? You went to K, right?" James queries her.
"You must have spotted a wrong name," Meowth suspects.
"I'm not blind, you animals! The twerp's name is really not in the list!" She then slams the logbook to their faces for them to check.
James and Meowth confirm what Jesse discovered.
"It's true. No name for Ash Ketchum," James says. "Maybe there might be a clerical error or something. Or a miscalculation."
"No, it means we're in the wrong ship!" Jesse growls at him, scaring him and Meowth. "Don't you get it!"
"Well, you're the one who is assigned to check the ferry schedule and what trip they are in," James points out.
This fact slows down Jesse from being infuriated. But she continues to show her rage as a defense mechanism. "So, I'm the one who is to blame?!"
Just to see Jesse infuriated makes James and Meowth shut their mouths from arguing against Jesse's defense. "Never mind," James mutters.
"Well, maybe we complain here all day," Meowth chillingly implies. "Or we could follow the twerps onshore right now."
"There's a time for everything, Meowth," Jesse says. "But it's time for me to pour out my rage!"
Suddenly, the ship suddenly gets hit by something, which leads for the passengers to lose balance and collapse to the floor, including Team Rocket. The entire vessel is rocking gradually from left to right, letting loose of its course.
Another hit trembles the ship and its passengers. The people try to rise up and to know what is going on. But another hit sends them back to the floor.
"What was that?" James asks.
At the very shore, some onlookers witness some water Pokémon panicking in the water. And for those with ability to walk on land, those Pokémon escape to shore and hide in the forest.
A Pokémon Ranger Rescue group arrive after receiving a distress call from the ship. Two rescuers dive to the water to investigate the tremors. But the ancient eel Pokémon starts attacking them. One rescuer tries to unleash his Buizel to attack. However the eels attack his arm and devour him wholly, leaving the Pokéball floating.
The passengers of that ferry check the water from what may have caused the tremors. But another hit takes them to their knees. The ship then tilts slightly to the left from the bow, leaving everyone off balance.
Team Rocket tries to escape but they end up dropping to the walls.
"What's happening?" James asks.
"Whatever it is, it's bad!" Jesse scolds at him.
Another hit comes. But the team escapes from their cabin and to the third level deck below. They hang on to the rails and cling on it by the elbow as the ship tilts to 25 degrees.
Meowth then sees something out of this world. "Jesse, James, check it out!"
Out of the blue ocean appears a frightening reptilian head with sharp teeth, armored skin, giant horns, amphibious gills and a strident snout. Not too far from the other head also appears an identical head, rising above. James then pulls his way to a better vantage point that shows to the windows to the other side of the ship.
"James, get back here!" Jesse insists.
Sure enough, as he squints, he sees two more similar heads rising above the water. "Guys, we better swim," he horrifyingly says.
Onlookers from the port town and most especially the ferry passengers are horrified to see a hydra-like Pokémon surrounding the ship.
From a distance, Ash witnesses this horrifying event unfolding. "Guys, check this out!"
"What is it, Ash?" Mallow asks.
He then points them to the ferry being under attack, bringing them to a surprise.
"What is that thing?" Lillie gasps.
"I better help them!" Ash insists. "Datrix, go!" Datrix then appears from its Pokéball. "Let's go!" The young trainer then holds on to the owl Pokémon's talons, and they head down to the ferry destruction.
"Ash, be careful!" Lillie pleads to him.
Back on the ship, seven heads officially surround the ship, frightening everyone aboard. Team Rocket finds their way out on time, just a giant claw scratches from the top deck until the third level deck. They dive their way to the ocean, just as the eels spot them. The hapless team leans on the cold metal below with nowhere to escape from the surrounding Ratman eel Pokémon.
"Well, if this is the end, I have a lot of words to say!" Meowth whimpers dramatically.
"We have no time for that, Meowth!" Jesse berates him.
"But we are surrounded by this Pokémon that I don't know," Meowth replies.
"Well, let's just hope that there's nothing worse than this," James says.
Timely enough, Bewear jumps from the ship and catches the antagonistic team. The eels ready to strike the bear Pokémon. But Bewear swims them hurriedly back to shore, with the eels on its tail.
"Don't know how you get here Bewear, but thanks…" Jesse remarks, just as they speed to shore.
The less goes to the passengers of the ship, who either dive out of the ship and swim to shore or retrieve lifeboats to safety.
But in an unprecedented move, one hydra head plunges to the core of the ship and sets its ablaze. Its claws then drag the damaged ship to the ocean deep.
Slowly, onlookers see the horror of a Pokémon consuming an entire passenger ship.
Ash most of all is horrified.