An unexpected revelation from Susan leads Finn closer to answers about his past.
Having remembered her real name and her memories, Susan takes Finn, Jake and BMO to an abandoned port with hopes of reactivating an old transport ship to get to Founders' Island. Just as Susan and BMO reactivate the transport ship, Susan reveals that he is taking Finn to see his mother, Dr. Minerva Campbell, on the island. Aghast and suddened by the revelation, Finn stares into the void.
A flashback starts with Minerva staring into the void from her car where she is taking a group of old women to their destination. Just as suddenly, a Martin Mertens jaywalks and angers Minerva who had nearly ran him over. Martin continues on with a steady smile while Minerva furiously speeds away. Martin arrives at a park where he takes off his earplugs and chews them like gum. He meets two people who want to leave the island and permits them passage for gadgets. Once the deal is made, Martin sends the two to the beach and secretly alerts the Seekers of their intentions. Before he could leave, Martin was confronted by the Widow who demands safe passage. Martin attempts to tell them to meet him at the beach but the Widow forces him to come with them.
After a confrontation with the Seekers, Martin is sent to the hospital for his broken legs. He is put under the care of Minerva who he attempts to charm his way out of the hospital. After Minerva catches him attempting to escape, Martin injures his lower body, fingers and head prompting Minerva to intervene. After a few hours of medical operations, Martin is once again on the bed and his body is mostly in a cast. Minerva is annoyed by Martin's arrogance but softens when Martin hints of attraction and his intention to go on a date with her. The two spend a night together but is cut short when the Seekers take him to re-education in the morning. Out of pity and infatuation, Minerva lies to the Seekers that Martin needs more medical attention and expects Martin to repay her by going on a date.
Minerva and Martin's relationship grew after their first date, with Martin supporting her in her Helper duties and getting a job as a barber. Minerva gets pregnant and after the following months she gives birth to Finn. The baby Finn, now a few months old, is left to the care of Martin while Minerva tends to her medical assignments. Left alone, Martin spends time with Finn but is abruptly stopped when the Widow and her bodyguards storm their home. They came for Martin for duping them to the Seekers but Martin flees the house with Finn in hand. They lose the group after boarding a raft out to sea.
Before Martin could text Minerva what had happened, a storm catches the raft and the Guardian surfaces from the ocean. After the Guardian misses hitting their raft, Martin leaves Finn behind but not before promising he will come back for him. Martin climbs the Guardian and destroys one of its eyes using one of his gadgets and the ensuing explosion hurdles Martin out to sea with the Guardian inadvertently pushing the raft carrying Finn away. The next morning, the Widow and her bodyguards are arrested with Minerva lamenting the loss of her love and son.
In the present, Susan and BMO manage to reactivate the transport ship and are bound for Founders' Island. Jake awakens Finn from his stare, saying he "hasn't said anything in a while."
- Susan Strong (Kara)
- The Widow's Tiger (flashback)
- The Widow's Bodyguard (flashback)
- The Widow's Henchmen
- Dr. Gross (flashback; cameo)
- Humans (flashback)
- The Guardian (flashback)
- The circumstances surrounding Finn's abandonment are revealed.
- Martin's ship in "The Visitor", The Minnie, is named after Finn's mother, Minerva.
- His explanation for Finn's abandonment in this episode is only somewhat accurate, as he says Finn was born on a boat, was attacked by seaweed, and attacked by a real bear and tiger. In reality, Finn was born on the human Islands, there was no seaweed, the Widow's tiger did not directly try to attack Finn, and the bear was actually just Finn's stuffed animal.
- The animation for Martin's boat being caught in a storm in "The Visitor" was re-used for this episode.
- It's revealed that the boat was actually a raft.
- Martin seems to have said there were bananas on the boat Finn was born on due to the fact that the family had a banana tree in their front yard.
- The fact that Finn was lost at sea as an infant is likely the reason for his former fear of the ocean.
- The episode briefly recaps what happened in "Hide and Seek" after Martin is taken to the beach by the Widow's bodyguard.
- Two Bread Tom, the leader of the tribe of humans Marceline helps in the Adventure Time Mini-Series: "Stakes", appears in this episode briefly as a statue on Founders Island. A plaque reads: "Thanks Two Bread Tom for being everyone's cool dad."
- Minerva being a doctor is most likely why Finn felt confident being a doctor in "Do No Harm".
- As of this episode, Susan has regained the ability to speak coherent English. She even mentions how good it feels to use big words again.
- The cause of Martin's mental state and sociopathic personality shown in his introduction in "Escape From the Citadel " and onward is explained by his head injuries, specifically his injuries from his fight with the Guardian.
- Sam Alden's promo art for the episode reveals the extent of the head injury Martin sustained from his fight with the Guardian. Judging by the blood, his expression, and the crew member of the ship that saved him, he most likely suffered severe brain damage.
- Finn's stuffed bear has a name tag on it. This is most likely how Finn kept his real name when he was found by Margaret and Joshua, as his hat was probably made out of the bear.
- Finn's hat was made because he remembered his mother's own bear hat.
- On Martin and Minerva's first date, Martin pays for their meal by using a large gem he found in his boot. The various objects that fall out of his boots as well as the water suggests that he really was some sort of explorer.
- This episode was released for digital download and DVD on January 24, 2017.