The Invisible Child is the twelfth episode in the first series of the 2019 television series Moominvalley.
Underneath a night sky lit with a green natural light display, Too-Ticky watches a cabin through binoculars. She shines a torch on a seemingly blank piece of paper which contains an unseen letter. Too-Ticky says that there is no house number mentioned in the letter, and no number on the cabin, so it must be the place she is looking for. She opens a window and sneaks inside the cabin, returning soon after with an invisible creature in tow, who she tells to stay as quiet "as a creep". Too-Ticky fastens a collar around the creature's neck, hoping that it isn't "too tight or too loose", although it is hard to tell. She tells the invisible being to follow her as she makes her way through the woods.
Moomintroll and Little My are picking mushrooms in the forest and comment on how it is hard to see through the dense fog surrounding them, as it looks like everything has "completely disappeared". Moomintroll worries about whether they will find their way home and Little My tells him that he won't get lost if he follows his nose, because "it's big enough", and he touches his nose self-consciously. Moomintroll hears a noise nearby but Little My dismisses it, saying that he's being followed by his own tail. Moomintroll follows the noise, thinking that it might be someone lost in the forest.
Not far away in the same forest, Too-Ticky loses the invisible creature when the leash comes loose, and she tries to re-trace her steps to find them. Moomintroll rests against a tree nearby and complains to himself about how Little My never listens to him as she is always "too busy" thinking about her next "clever remark" whenever he has something important to say. Moomintroll hears a voice and looks around to see a silhouette of a girl in the fog before it quickly disperses, and he jumps up in shock and runs away, knocking over his basket of mushrooms. Moomintroll calls out timidly, asking if there is "any body there" and then sees his mushrooms seemingly place themselves back in his basket - collected by invisible hands. Moomintroll thanks the invisible person when they hand him his basket, commenting that they really did lose themself "in the fog" as they've "completely vanished". Moomintroll and the invisible creature create a system of communication with two knocks meaning yes, and one knock meaning no. Still somewhat afraid, Moomintroll invites the invisible person back to his house with him, as "Mamma will know what to do".
Back at Moominhouse, Moominmamma, Moominpappa, Little My and Moomintroll clean the mushrooms picked in the forest. Little My is frozen as she looks over at their invisible guest, who is also cleaning mushrooms, and Moominmamma tells her not to stare as it is "impolite". Little My remarks about how Mamma knows that she is staring at them, when they can't see "where they are". She then suggests that the invisible person eats a mushroom as she might get to see it "go down inside". Moominpappa wonders how they can help someone turn visible, and Moominmamma says that they should just let their guest "settle in" and see what happens, so which Little My replies: "watch this space".
That night, Moominmamm and Moomintroll bid their invisible guest goodnight in their spare room, and Moominmamma presents them with a small bell to wear around their neck if they "feel like being heard". She also tells the invisible person to sleep in "as late as you like" and to come and find them if they have a "funny feeling" in the night. The invisible person surprises them with a polite cough, revealing that they hadn't got into bed yet, and then climbs in, and Moominmamm and Moomintroll bid them goodnight and leave. Moominmamma reminds Moomintroll that the invisible person should only wear the necklace "if she wants us to know where she is". Alone in the room, the invisible guest picks up the bell.
The next morning, Moominmamma, Moomintroll, Little My and Moominpappa are gathered around the breakfast table. Moominmamma searches in "Granny's Book of Cures" to see if there is anything about being invisible. She finds a remedy for people who become "misty or difficult to see", however it just says to listen. Moomintroll puts his ear to the book, however he can't hear anything, and Little My tells him that "books don't talk" and that Granny is having a joke on them from "beyond the grave". Moominpappa says that they can cure their invisible guest with their "tip-top problem solving instincts" as he tries to remove the lid from a jar of honey, which Moominmamma opens for him by tapping it against the table. They all hear a tinkle of a bell as the invisible person comes downstairs, the bell on the ribbon visible around her neck. Moominmamma offers their guest some breakfast, and her paws suddenly appear, which Moomintroll points out in excitement. Little My says that the invisible girl must look "an awful fright" if she keeps her face hidden. The paws disappear as their guest gasps in shock. Moomintroll tells Little My that it is her fault that the invisible girl is invisible again, and Little My says that the girl is "too timid" and that she'll never have a face of her own until she's learnt to stand up for herself. Moomintroll tells the invisible girl not to listen to Little My, as she's as "hard boiled" as her own egg, and invites their guest to instead join him for breakfast outside where they "won't be insulted".
Moomintroll and the invisible girl go apple picking, which at first results in Moomintroll having apples dropped on his head, but they soon create a system so that he can see which apples will be dropped. He tells their invisible guest that "being useful" will take her mind of being see-through "in no time" and that they can use the apples to make apple juice. He says that, if she is feeling "distracted enough", then the invisible girl can "go ahead and become solid" if she likes. Moomintroll then cries out that it is working when he realises that he can see the invisible girl's feet standing on the ladder in the apple tree. Suddenly Moominpappa jumps out from the other side of the apple tree shouting "boo!' and scares the girl, causing her to fall from the ladder and become invisible again, before running away, knocking over a glass jar and the apples. Moomintroll crosses his arms and looks at his father with a frown, and Moominpappa explains that he thought being invisible was perhaps like having hiccups, and that he thought the girl needed "a good fright". Moominpappa awkwardly excuses himself, and Moomintroll joins Moominmamma, who is sweeping up the jar. The two of them notice the invisible girl hiding in the bushes nearby, and Moominmamma says that it was a happy accident that the jar was broken, as she never liked it and will never have to see it again. Moomintroll also joins in with trying to make their invisible guest feel better, saying that he is "so happy" that the invisible girl is here, however Moominmamma tells him not to "overdo it". The invisible girl leaves her hiding place and joins them, and Moominmamma thanks her and tells her that it was a "good deed". Moomintroll notices that the girl's bell is tinkling, and wonders if she is trying to tell them something, to which Moominmamma replies: "she's cold".
Back inside Moominhouse, Moominmamma has made their invisible guest a new set of clothes and a bow for her hair, which are visible as she tries them on. Moominmamma folds up the old, invisible clothes, and tells the others that the "poor thing" must have been freezing, as her old garments are "virtually threadbare". Moominmamma says how she hasn't been able to sew a nametag in the clothes, as she doesn't know the girl's name. Little My suggests that they give her a name, and Moominpappa offers "The Contessa". Moomintroll hears something and tells the others to be quiet and listen. The invisible girl tells them that her name is Ninny, and the family reacts with happiness. Moominpappa announces that, now Ninny can talk, she can critique the latest chapter of his memoirs, and he pulls up a seat to sit in. Moominpappa begins to read his story while the others sit down, however their listening is interrupted by Sniff arriving and trying to talk to them. Sniff sees the seat that Ninny is sat in and mistakes it for clothes resting on an empty seat, pushing Ninny out of the way so that he can sit down. The others react with shock, and Ninny runs upstairs in terror. Sniff tells Moomintroll that he has "haunted clothes", and jumps out of the window. Moominpappa continues his story.
Moomintroll leaves his father's storytelling to search for Ninny, who he finds hiding in the corner of Moominpappa's study, crying. Moomintroll apologises on Sniff's behalf and asks Ninny if she is okay, which she responds to with two knocks, having returned to being silent. Moomintroll sits with her and says that he wishes he knew how to help her, however it is hard when they don't know "the first thing" about her. He looks at a map of Moominvalley hung up on the wall and remarks that they don't even know where Ninny comes from. Ninny joins him and places a pin in a spot on the map where a small cabin is, showing Moomintroll where she comes from. Suddenly, a bright light is cast on them and Little My shouts "gotcha!", causing Ninny to run away again and Moomintroll to become cross. Little My follows after Ninny with the torch, calling out: "I've got a shadow, what have you got?" Moomintroll tells Little My that he has a "brilliant idea", and he talks about Moominpappa's latest story, saying that if his Pappa had to return home to find himself, maybe it could help Ninny. Little My takes a mirror and leaves, saying that she is going to see if Ninny has a reflection.
The next morning Moomintroll wakes up Ninny and invites her to go mushroom picking with him. He is happy to find that she is speaking again, and she joins him. Moomintroll talks almost constantly during their journey, with Ninny finding it hard to reply. Moomintroll tells her that he thinks that everything will be a lot clearer soon, including her, and, with his encouragement, she says that she would like that.
Back at Moominhouse, Too-Ticky arrives on the doorstep looking very upset. Moominmamma and Too-Ticky talk over tea about the person she has lost and Too-Ticky says that it's hard to say what she looks like, which is why she's been hard to find. She says that Ninny is as "see through as a window" and Moominmamma reacts with shock at the familiar name, and tells Too-Ticky that Ninny has been staying with them. Too-Ticky is relieved and asks if she can see her and Little My tells her that it isn't possible; not just because she is invisible, but because Moomintroll has taken her mushroom picking, using Little My's basket. Too-Ticky begins to ask more, however Moominpappa interrupts them when he appears and shouts "vandalism!". Moominpappa shows them the pin in his map, complaining about how it is "virtually ruined". Too-Ticky pulls out the pin and looks at the cabin on the map, saying that she thinks she knows what's happened.
Back in the forest, Moomintroll telling Ninny about his adventures with a little ghost. As they get closer to the cabin, Ninny starts to slow down, however Moomintroll encourages her to hurry forward and presents the cabin to her, saying that she is "home sweet home". Ninny tries to protest as Moomintroll pulls her towards the cabin, however he doesn't hear her. When Moomintroll knocks on the door, a Hemulen appears at the door and rudely asks if Moomintroll is a "bear or something", to his surprise. Moomintroll tells the Hemulen that he has great news for her, however she thinks he is a salesman and she tells him that she likes her windows dirty, saying: "what you can't see won't trouble you". Moomintroll explains that he is here to bring Ninny home, and presents her to the Hemulen, who puts her hands on her hips, looks down at Ninny and tells them "I didn't care she'd gone". Ninny runs off crying and Moomintroll tells the Hemulen that, whoever she is, she "never deserved" to look after Ninny, and then chases after the invisible girl, apologising. The Hemulen says to herself how she "never wanted" to look after Ninny in the first place, and then walks into her front door when it has closed behind her.
Moomintroll searches for Ninny in the forest without luck and says to himself: "what have I done?" He hears Little My say that he hasn't been picking mushrooms, "that's for sure", and finds Moominmamma, Moominpappa, Too-Ticky and Little My in the forest, also looking for Ninny. Moomintroll apologises to them, explaining that he thought that if he took Ninny home, she would be alright. Too-Ticky explains that she found a note from Ninny a week ago that was asking for someone to rescue her from her "nasty aunt", presenting the seemingly blank letter. Too-Ticky continues to tell them that the aunt had ignored and neglected Ninny so much that the "poor little lass" had completely faded away. Moominpappa studies the letter and asks how "on Earth" Too-Ticky could read the letter, and she shines a torch on it and Little My points out that the invisible writing makes a shadow, like Ninny herself. Too-Ticky says how she was going to take Ninny to live with her when they got lost in the fog.
Moomintroll looks very miserable, saying that they might have lost Ninny forever. Moominpappa reassures him that he tried his best, and says that he knows how to make Ninny come back: "another thrilling passage from my Memoirs!" Little My says that they should instead use the torch to find Ninny's shadow, and then catch her in a net. Moominmamma says that they should simply call her name, which they all begin doing. Moomintroll stops them suddenly, saying how they all think they know what's best for Ninny, but that maybe the only way to find out what she wants is to stop talking and start listening. Moominmamma says that it is just like it said in Granny's book. A bell quietly tinkles nearby, and the group follow the sound until they are near the lake. Moomintroll finds the bell hanging from a branch, commenting that it seems Ninny doesn't want to be seen.
Moominpappa suggests that Ninny may have merely disrobed to go for "a dip" in the lake, and Little My tells him to "look for a hollow in the water" as he approaches the lake. Moominpappa leans over the lake and begins to call out for Ninny when a head appears from a nearby bush - a girl with ginger hair in a bow. The girl leaves the bushes and Moomintroll realises it is Ninny herself, saying "I can see her!" Ninny gestures with a finger to her lips for him to be quiet, and she creeps up behind Moominpappa and yells "boo!", causing him to fall into the water in shock. Ninny says that will teach Moominpappa for making her jump, and the others laugh before going to join Ninny. Little My congratulates her on standing up for herself, and Moominmamma tells her that she is "as sweet as a fresh pea". Moominpappa disagrees from within the lake, complaining that Ninny is the silliest, nastiest, badly-broughtuppest child he's "ever seen" - with or without a head. Moominmamma, Moomintroll, Ninny and Little My laugh in response, much to Moominpappa's distress, and Moominmamma eventually helps him out of the lake.
Moomintroll notices Too-Ticky stood nearby and joins her, and she tells him that winter is coming, and that she expects the Moomins will be hibernating soon. The two of them watch as Moominmamma and Moominpappa embrace Ninny, and Moominpappa thanks her when she gives him back his hat. Too-Ticky tells Moomintroll that she has some good friends that Ninny can stay with, but says that she needs him to keep listening for her. The two of them walk away to look out at Moominvalley, and Too-Ticky tells him that there are lots of other lost souls out there who need to be heard. It begins to snow, and Moomintroll stares out over the valley as the snow clouds gather. Within the forest the snow begins to cover the trees and Snufkin travels on his journey southwards.