A character gets an illness or an injury and another character spends most of the episode nursing him back to health. By the end of the episode, the "patient" got over his illness, but realizes The Caretaker has caught the illness from him. He decides to take care of the now "patient".
It doesn't have to be illness or injury. Sometimes, it's when a parent used to take care of the child and, a few years later, the child takes care of the aging parent. May also happen to the Cloudcuckoolander's Minder if they take a blow to the head or visits Cloudcuckooland.
This can be Truth in Television In many families with small children and a stay-at-home parent. It's not rare for the stay-at-home parent to get an infection from the kids before the parent who works outside the house. Also, if a person gets an illness and accidentally spreads it to another member of their household, they might recover before the other person does, leading to this trope.
- In an episode of Midori Days, Seiji accidentally drinks a bottle of sake, and Midori tries to take care of him (including scaring off door-to-door salesman by impersonating a zombie). When he wakes up, he feels great, but Midori is sick. However, in the manga, Midori gets sick first.
Seiji: My right hand caught a cold...?
- Happens in one episode of Sailor Moon R, when Minako plays nurse to her friends, but ends up sick herself by the end of the episode, when Usagi and Chibi-usa return the favor.
- In Trinity Blood, after Ion is shot by Tres, Sister Esther ends up caring for him (including replacing his bandages). A few episodes later, Esther is knocked unconscious and wakes up to find Ion at her bedside.
- In Kamisama Kiss Nanami is an Ordinary High-School Student who winds up with a Little Bit Beastly Kitsune, Tomoe, as familiar. However, when Nurakami uses a magical artefact that turns Tomoe into a child Nanami ends up caring for him. Also, when Nanami winds up playing around with time travel she winds up rescuing a wounded Tomoe from a riverbank in the past and nursing him back to health.
- In Mini Sengoku Basara, Motonari has a fever and Motochika insists on trying to cure him by strapping a fish to his head and cooking up some stew which looks...kinda like the inside of a black hole. Later Motochika gets sick and receives a visit from Motonari, who repays him in kind.
- A variant occurs in Pokémon. A flashback shows that Ash and Serena first met in a summer camp when Ash came upon an injured and lost Serena in the woods, bandaging her injured leg and leading her back to their camp. In the present time, during, coincidentally enough, another summer camp, Ash and Serena fall off a cliff, but this time around, Ash is the one who got an injured leg in the process, so Serena had to take care of him until help arrived.
- Subverted in Himouto! Umaru-chan: In one arc Umaru gets sick and expects her brother Taihei to baby her, but he has to work. When Taihei ends up catching Umaru's cold, she plots her revenge by subjecting him to nasty "cures" like shoving a leek up his butt...but then she feels genuinely guilty when she sees how sick he is and actually proper care of him.
- Invoked, then subverted in Miss Kobayashi's Dragon Maid: Kanna's Daily Life. Kanna takes care of Saikawa when she comes down with a fever, then tries to catch a cold herself a few days later so Saikawa can take care of her. Being a dragon, she has Ideal Illness Immunity, so her attempts to get sick fail.
- The minuscule mummy Mii-kun of How To Keep A Mummy is generally too small to be able to take care of Sora during the show's Sick Episode. He's still able to help by using his own body as a cool washcloth for Sora's forehead. It's all well and good, except by the next day it turns out Mii-kun has caught Sora's cold.
- In Pokémon Reset Bloodlines, Ash gets badly injured saving his Pikachu from a flock of Spearow, and Misty takes him to the Viridian City Pokémon Center. Later, Misty gets poisoned by Vileplume pollen, so Ash has to take her to a hospital in Cerulean City.
- Murder by Death: Happened during the backstory, where Miss Marbles has a nurse but Miss Marbles takes care of the nurse, rather than the other way around.
- The Avengers (1998). After Steed is attacked by Mrs. Peel's clone, the real Mrs. Peel takes him to her home to recover and nurses him back to health. Later on, after Mrs. Peel is captured and brainwashed by Sir August, Steed rescues her and takes her to his home to recover.
- In the Akira Kurosawa film Red Beard, Dr. Yasumoto takes care of a feverish girl, abused to the point of madness, named Otayo. When the doctor himself falls ill, Otayo tends him, which helps her mental recovery. (In an amusing bit, she even tries reading his medical texts to stay awake.)
- In Ivanhoe Rebecca first acts as Ivanhoe's caretaker, then Ivanhoe acts as her champion.
- In Ethan Frome, this happens three times with Zeena: Before their marriage and life together in Starkfield, Zeena was healthy and knowledgeable about medicine, taking care of Ethan's mother. During the majority of Ethan's story, Zeena spends her time claiming that she's ill and having Ethan care for her. Then, after Ethan and Mattie's Bungled Suicide, when they both acquire crippling injuries, Zeena takes care of them, even 20 years after the accident.
- In Frog and Toad, Toad tries to cheer up Frog because he's sick. Frog gets better but then Toad gets sick and Frog takes care of him.
- Flip-flopping through this trope is how Jaime and Brienne's friendship gets started in A Song of Ice and Fire. Originally, Brienne is Jaime's guard, and has to protect him from all kinds of dangers (including some that he gets into on purpose to get on her nerves). Later on, when the two of them are taken prisoner by the Bloody Mummers, Jaime winds up spending a lot of time protecting *her*, since of the two of them, he's the hostage who's too valuable to kill, and therefore has a little bit of leverage. By the time they're freed, they're pretty much protecting one another.
- The ending of Bear Feels Sick in Karma Wilson's Bear series has all the other animals catching Bear's cold and Bear taking care of them the way they took care of him.
- Our Miss Brooks: A Caretaker Reversal revolving door, in "Old Age Plan."
- The story begins with Mrs. Davis having cared for her sister Angela, and falling ill from Angela's complaining. By the end of the episode, Mrs. Davis has recovered and Angela has again become ill from Mrs. Davis' complaining.
- Meanwhile, Miss Brooks had spent the episode shilling Mrs. Davis and Angela's club's old age plan to Mr. Boynton and Mr. Conklin. The two men end up suffering psychosomatic symptoms of old age.
- Miss Brooks decides to invite them over to Mrs. Davis' house, and fake the symptoms of old age to distract Mr. Boynton and Mr. Conklin from their symptoms. The climax of the episode has Miss Brooks, Mr. Boynton and Mr. Conklin rapidly experiencing illness and being placed on the sofa with a blanket and ice pack in turn.
- The M*A*S*H episode "Carry on, Hawkeye" is mostly about the majority of the camp (including three of its four doctors) falling ill, leaving Hawkeye and Margaret to run things. At the end, Hawkeye finally succumbs to the flu as the rest of the camp begins to recover. In the final scene, he's a) almost alone in the post-op and b) the recipient of the camp's gratitude.
- In an episode of How I Met Your Mother, Robin is sick and Ted takes care of her. When he goes to kiss her, she tries to refuse, but he goes ahead anyway. Immediately after, we see Ted in bed, Robin taking care of him.
Ted: So worth it.
- The Big Bang Theory: in season 1, Sheldon gets sick and makes Penny take care of him. In season 3 Penny gets injured and makes Sheldon take her to the hospital and take care of her afterward. What connects these two instances most solidly is the song "Soft Kitty." Sheldon teaches the song to Penny to sing to him ('cause that's what his mother did when he was sick as a youngster). Then when Penny is injured she makes him sing it to her.
Penny: Sing "Soft Kitty" to me.Sheldon: "Soft Kitty" is for when you're sick. You're not sick.Penny: Injured and drugged is a kind of sick.
- Played for Drama in the second episode of Dr. Quinn, Medicine Woman, Dr. Mike works herself to exhaustion during a deadly flu epidemic and must be cared for by Sully when she catches the disease herself.
- Kung Fu: in "Besieged: Cannon at the Gates", Caine is lying on the ground mortally wounded after he sabotages a cannon firing at the Shaolin Temple, and his Girl of the Week is leaning over his body comforting him. Then the Dragon with an Agenda stabs her; she becomes limp, and Caine reverses positions with her as she dies. Suddenly he's fine. See it here, starting at 3:55.
- On an episode of The Rifleman Lucas takes care of Mark who has the measles. At the end, Lucas has the measles while Mark takes care of him.
- Horatio Hornblower, "The Duchess and the Devil": While imprisoned in Spain, Horatio saves his suicidal, starving friend Archie and nurses him back to health. Later Horatio gets tortured (he is put in a small hole in the ground for a week) and then Archie helps him.
- In the beginning chorus of Jamie O'Neal's "Somebody's Hero", the titular "hero" is a mother taking care of her young daughter. In the ending chorus, the roles have swapped, and now it's the daughter taking care of her aging mother.
- The Mrs Hawking play series: Before coming to work for Mrs. Hawking, Mary's sole occupation in life was to keep house for her father and take care of her unwell mother, causing her to see her only worth and purpose was her usefulness to others.
- Adventure Time: In "Storytelling", Jake gets sick and Finn takes care of him, obeying all of Jake's requests, including the one to find a true story to tell him. At the end of the episode, Finn gets sick as well, and Jake rushes to do everything for him as well...until he realises that Finn has just fallen asleep.
- Happens in the Rocko's Modern Life episode "Yarn Benders", which begins with Filburt getting sick after being caught in the rain and ends with Rocko and Heffer catching the illness after mangling a few fairy tales that they're reading to Filb.
- "Is There An Ed In The House" of Ed, Edd n Eddy. At the beginning, Sarah has a cold, and Double-D, Ed, and Jimmy take care of her. Near the end of the episode, Double-D comes down with Sarah's cold, which leads to Jimmy rushing up to Double-D saying: "Jeepers! You sound sick, Double-D! You shouldn't be outside; you need some TLC, mister!" He leads Double-D back into his house to take care of him, much to Double-D's objections while Eddy just stands there.
- The Ren & Stimpy Show: The episode "Nurse Stimpy" has Stimpy tending to a sick Ren and trying to cure him in his own stupid ways. At the end, when Stimpy gets sick from all the grueling work, Ren is a little too eager to return the favor.
- The Tick: "Tick vs. The Uncommon Cold'": The episode Bookends with Arthur bringing Tick soup in the opening and Tick returning the favor in the closing scene.