The S.S. Oceania is where the player officially begins their journey in the Aevium region. A luxury cruise traveling to various ports, Yancy chose to board along with her child to their new home in Aevium, as she was an old friend of the captain, Augustus.
The player starts off at a computer, beginning the registration process with Amaria. After being told about the general mechanics of the Aevium league, the player is given their trainer card and exits the room. Yancy happily greets the player, and encourages them to enjoy themselves. The player may roam around the ship and collect items or meet interesting characters, such as the friendly pianist, or Paul, who spent hours trying to fix a healing machine while under the impression that it was a milkshake machine.
In one room, the player can listen through the walls to listen to a strange conversation-and one involving their mother, no less! A strange woman with a Gothitelle commands Yancy to keep some unknown duty and situation in mind, including the possibility of severe consequences. Yancy expresses that she is aware of both, but has begun to feel fear. The woman scoffs and tells her she is only feeling faux emotions, but the woman begins to have questions herself after this information. Yancy is told to go to the banquet, as the woman "wants to see <player> smile."
This event does not have to be seen in order for the story to progress, but it does add new knowledge of the events that follow.
To continue the storyline, the player must speak to Captain Augustus on the top floor. Augustus explains some more aspects of the Aevium League to the player before realizing it's just about time for the banquet to start. He leaves his room, as do all the other passengers of the ship, though the player is not required to go to the banquet until they are ready.
In the banquet room, the traditional celebration has begun, but it is soon interrupted by an alarming threat-a woman in a strange uniform has declared a bomb is in the underbelly of the ship! Yancy turns to the oddly silent woman across from her and orders her to get the player out. The player is mysteriously teleported to the Captain's cabin just before the explosion.
In the cabin, the player can see the wreckage caused by the explosion, but they also discover something even more alarming-strange tentacle-like beings are reaching out of the floor! As the player steps down to the floor below, they see that these tentacles are ensnaring passengers and carrying them through holes-and as the surviving pianist explains, they appear to be able to sense movement! Stranger still are the odd creatures seen on the decks, making eye contact with the player but never approaching them.
After making their way back to the banquet hall, the player encounters a downtrodden Augustus, mourning the loss of his ship and passengers. He informs the player that Yancy has gone into the depths of the wreckage, to attempt to save what can be saved. Augustus tries to sway the player away from following her, but realizing this is futile, tells the player how to reach her without jumping into a massive hole.
The player finds Yancy finishing the last of the fires with the aid of her Sylveon. Yancy comments that the worst seems to have passed, but a mysterious figure warns her not to jump to conclusions, with two of the strange creatures behind him. He declares that the entire attack was due to her apprehension, and that all the bystanders were taken to prevent any witnesses. An attempt at night, he explains, was not an option, as they could have encountered "her".
Yancy tells Sylveon to get ready for a fight, but Sylveon falls quick to the creature (now known as Dexoy) firing a Flash Cannon at her. Yancy begs the player to take her Pokémon and escape, while the figure mocks the sight before him, claiming he'd "cry if I had a properly functioning non-physical heart". Yancy is ensnared by the tentacle beings, and the player is nearly trapped by a Dexoy as they exit, but a fallen piano has saved them from two floors up! Sadly, the pianist isn't able to escape another swarm of Dexoy herself, and as the player exits to the left deck, it looks like they might be in for a similar fate-but just in time, a Talonflame rescues the player with Flare Blitz and carries the player to Oceania Port.
- The computer in the registration room lists "<player>, Donald, Ren, Sarah, Aelita" as recently-registered trainers.
- This location contains a number of references to other media:
- One character talks about a book called How to Train Your Dragalge, a reference to the book/film How to Train Your Dragon.
- Another character mentions his mother is from Apophyl Island, a location in Pokémon Reborn.
- The Team Xen member makes a reference to Harry Potter when she interrupts the banquet.
- Various characters foreshadow the attack on the ship:
- One character mentions a dream of being abducted by aliens.
- A trio of schoolchildren lament having to return to school, and one hopes that something will happen to let them avoid it, causing another to fear she's jinxed them into something bad happening.
- Though not likely referencing the event itself, an elderly woman refers to Sheridan Village as her "final destination". The Final Destination movies typically began with a disaster striking a machine carrying a number of people.
- Two doors (excluding the one in which Nancy holds her conversation) are locked and never become accessible to the player: The leftmost door in the bottom floor, and the southernmost door in the main floor.