The Baudelaires tap on the hatch of the submarine, yelling for help. A woman calls through the periscope, asking for the password. When Sunny says that they're Baudelaires, the hatch opens and the siblings descend. Once they do, the hatch closed behind them and the sub submerges beneath the ice. The woman directs them via the intercom to a map room, and they figure the captain is looking for something. Captain Fiona Widdershins comes out and welcomes the Baudelaires to the Queequeg. She says that she's surprised to find them in the middle of the ocean, and hasn't been captain for long. Her stepfather, the original Captain Widdershins, left to answer a distress call from a manatee and never came back. Fiona insists that he'll find her.
The Baudelaires ask Fiona to take them to the Last Safe Place, but Fiona tells them that she's already on a mission and can't take them to shore. Klaus offers to help her with her mission if she takes them to the Last Safe Place afterward. Violet notes that they don't know what the mission is, but Fiona says that it's the most important mission in VFD history: she's searching for the sugar bowl.
Olaf hands out disguises to Hook-Handed Man, Esme, and Carmelita. They then go to a submarine rental company and Olaf asks to rent a submarine so they can hunt orphans at the bottom of the ocean. The rental worker asks if Esme is Esme, and says that her submarine is ready. She says that a couple called over the phone, arranging the rental of their most terrifying submarine for Esme, and said that Esme was captain. They board the submarine with tentacles.
Fiona says that one of the VFD agents was taking the sugar bowl to their HQ in the Valley of Four Drafts. The sugar bowl fell into Stricken Stream and was carried out to sea. Both sides of the VFD schism are after it, and the reason why is top secret. Fiona mentions her cook, Cookie, and calls him in. It's Phil, who is happy to see the Baudelaires and vice versa. Phil is still inevitably optimistic, and explains that his leg was eaten by a shark and he got to see it up close. The only thing he can cook is gum so they're having gum casserole for supper. Sunny offers to help cook and Fiona directs them to the ship's uniforms so they can change. Klaus is glad to help her as a researcher, but Fiona is a mechanical genius and doesn't need Violet's help.
In the barracks, Violet says that they should be searching for the sugar bowl and thinks that there's something wrong about Fiona. She is worried about Quigley but is sure that he's safe because of how resourceful he is.
At the bank's Department of Orphans Affairs, Quigley tells Poe about tobogganing down the waterfall and made his way back to the city on skis made from tree bark. Poe gets a call and then says that he can't help Quigley find the Baudelaires. He calls in his new secretary, Kit, who says that he's not Poe's secretary but she can help Quigley and shows him the VFD telescope.
On the terrifying submarine, Olaf complains to Esme that she's mean and tyrannical. He says that they should be hunting Baudelaires, but Esme says that they're going after what she wants: the sugar bowl. Carmelita comes in and tap dances, wearing a fairy princess outfit. Olaf goes off to drown his sorrows and finds Hook-Handed Man making dinner. He notes that they're calling their sub Carmelita per Carmelita, and tells Olaf that he can still "count" on him. Olaf tells Hook-Handed Man that he works for him and he expects him to obey his commands.
Klaus, Violet, and Sunny join Fiona in the library, and Fiona shows Klaus her favorite books about mushrooms. Violet notes that it would be easier to calculate where the tides took the sugar bowl if they knew what was inside, and Fiona irritably reminds her that the contents are confidential and orders her to get to work. Once Violet leaves to check the sonar equipment, Fiona apologizes to Klaus and says that she's been under a lot of pressure. She says that her father never told her what was in the sugar bowl, and her brother died in a manatee accident. As Fiona starts to tell Klaus about her family and pulls out a family history book, Klaus finds a book on the water cycle and Fiona drops the subject.
In the galley, Phil and Sunny make gum casserole with potatoes, flour, cream, black pepper, and cod. Sunny suggests that they make chowder and peels potatoes with her teeth.
Violet checks the airlock and Klaus finds her. He explains that Fiona doesn't know what's in the sugar bowl, and says that Violet should try to get along with Fiona. Back with Fiona, Klaus calculates that the sugar bowl was carried to a small island marked "Anwhistle Aquatics". "Anwhistle was Josephine's last name, , and the place was a marine research and rhetorical advice center that her husband Ike ran with his brother, Gregor. The brothers had a falling-out and never spoke, and a fire destroyed the center and killed Gregor. The sugar bowl is apparently under the center, in the Gorgonian Grotto. Fiona says that they shouldn't rush going there, and Violet insists that they're running out of time.
Both girls turn to Klaus, but before he can say anything Phil and Sunny arrive with chowder. Fiona decides to set sail for the Grotto immediately.
Olaf and the others complain about Hook-Handed Man's salad, and Olaf tells him to go eat in the brig with the rats.
Violet asks Fiona for what's going on, and Fiona finally says that the Medusa Mycellium is in the Grotto. It's a rare mushroom that only grows there, and it's deadly poisonous. It waxes and wanes in cycles, and is dangerous when it waxes. The sonar detector goes off, revealing something coming up on them. Fiona orders everyone to turn off the lights and engines so it won't see them, and they see a monster through the porthole. It passes on without seeing them, and Fiona explains that it's the Great Unknown and it's always out there waiting in the darkness. Jacques' brother wrote about it, and Fiona goes to read the book in the library.
In the library, Fiona looks at photo of her younger self and her stepfather.
On Carmelita, Olaf is sad that he has sunken so far because he doesn't have the Baudelaires to torment. He tells Carmelita that looks fade and she breaks into tears. They spot the Great Unknown on the sonar and Olaf has Hook-Handed Man turn off the lights. It finally leaves and they spot the Queequeg.
The Baudelaires spot the Carmelita and assume it's an octopus.
Olaf and Hook-Handed Man recognize Widdershin's submarine, and Olaf figures that he can tell them where the Baudelaires are. Esme insists that they go after the sugar bowl, and Olaf takes her captain's hat and heads for the Queequeg.
The Baudelaires see the Carmelita approaching and realize that it's a submarine. They sail away and Olaf closes on them, his laughter restored. The Carmelita grabs the Queequeg with its mechanical tentacles and locks on a boarding tube. Olaf and Esme come aboard and the Baudelaires quickly close the door to the control room. Phil steps out and compliments Esme on her new octopus-based outfit, and then apologizes to the Baudelaires for giving them all away. The Baudelaires emerge from hiding and Olaf rips apart the control console. When Olaf wonders where Widdershins is, Klaus explains about the manatee distress call and Olaf wonders who the captain is. Violet claims that she's the captain, yells "sea monster" to distract the intruders, and tries to run with her sib lings. They grab Phil and the Baudelaires, and Esme sees "Sugar Bowl" written on the map leading to the island.
Olaf and the others put the Baudelaires in diving suits, shove them into the airlock, and tell them to recover the sugar bowl. Olaf warns them that they don’t have enough oxygen to get away, and the Baudelaires go out. As they drift down to the bottom, they see Fiona working in the library.
Olaf and Hook-Handed Man look at Fiona's portrait of Widdershins, and Hook-Handed Man wonders what happened to him. He suggests that he should search for stowaways and Olaf agrees.
Fiona sends an SOS by telegraph, and Poe gets the message. He's busy with paperwork, and tells Kit that since the fires the orphans have all gone missing. Kit reminds him that she's just there to use his telegraph, and a Volunteer Factual Dispatch arrives for Kit from Fiona, saying that the mission is compromised. Kit sends a message back saying that she's sending help. Hook-Handed Man approaches the library, and Fiona hears him coming and hides beneath the desk by the time that he enters. He looks at a sextant on the desk and starts to peer under the desk, but the telegraph goes off. Hook-Handed Man smashes it and leaves, but comes back as Fiona emerges from behind the desk.
Kit makes a call for help.
The Baudelaires enter the Grotto and climb a ladder up to a stairway leading to what's left of the center. Klaus refuses to leave Fiona on the sub, and Violet says that they'll discuss it once they find the sugar bowl. They realize that VFD was doing experiments there and Violet finds a wire from "Fernald" telling Gregor to reconsider his project. There's no sugar bowl, but they find an imprint of a sugar bowl in the dirt and footprints leading away. The footprints lead up the stairway going up, and Quigley calls down to them from the top. He says that VFD sent him and he got the sugar bowl, and he'll tell them everything when they come up.
The Medusa Mycellium waxes on the cell and Violet is forced to leap off the stairs, touching the Mycellium on the railing. She calls to Quigley to leave before the Mycellium reaches him, saying that they'll meet at the Last Safe Place and take the sugar bowl with him. Quigley closes the door just in time and the Baudelaires suit up and go back to the Queequeg.
Hook-Handed Man tells Olaf that he didn't find anyone, and Olaf has him take Phil to the Carmelita. The Baudelaires signal their return.
Quigley telegraphs to Kit that the sugar bowl is safe and the Baudelaires are in danger.
In the airlock, the Baudelaires remove their suits. Klaus realizes that there's Mycellium inside of Sunny's suit, as Olaf looks in through the airlock door and laughs.
Written by Gadfly on Feb 4, 2019