Whilst running to the first day of her new school, the happy-go-lucky Hoshizora Miyuki encounters a fairy named Candy, who leaves behind a pink book. As Miyuki has trouble introducing herself to the class, her classmate Hino Akane helps her to break the ice. As Miyuki checks out the library later that day, she discovers a mysterious entrance, taking her to a strange place where she learns Candy is being chased by a wolf named Wolfurun, who starts making the people in the town fall into despair and steals their 'bad energy' with a goal of resurrecting someone named Pierrot. As Miyuki strives to protect Candy, she is given a magical item known as the Smile Pact, using it to transform into a Pretty Cure named Cure Happy. As Miyuki becomes reluctant to fight, Wolfurun summons an Akanbe monster to fight against her, but with help from Candy, Miyuki manages to realize her power and defeat it, receiving an item known as a Cure Décor. As Wolfurun retreats and happiness returns to the townspeople, Miyuki decides to help Candy in her quest to recover Cure Décors and save her kingdom.

After hearing from Candy that she needs to gather four more Cures, Miyuki mentions it to Akane and her other classmate, Kise Yayoi, though Akane turns down the idea to focus on her volleyball training. Later that day, Miyuki notices Akane downhearted over a volleyball slump, so she decides to help her practise. However, during Akane's volleyball match the next day, Wolfurun appears to steal their bad energy, creating a volleyball Akanbe. Miyuki transforms to fight against it but loses energy when her finishing attack misses. When Akane realises Miyuki is in trouble, she overcomes her despair and stands up to the Akanbe, gaining the power to transform into Cure Sunny and defeat the Akanbe. Afterwards, Miyuki and Akane decide to become good friends.

Having taken notice of her drawing talent, Miyuki and Akane nominate Yayoi to design a poster for a school contest. Yayoi herself does not have much confidence in her ability, but Miyuki and Akane encourage her to give it a try and agree to help. Yayoi eventually manages to finish the poster, but becomes downhearted when it does not win, making her a target for another villain, Akaoni, who makes an Akanbe from Yayoi's poster. As Miyuki and Akane end up exhausting themselves too early and struggle to fight against the Akanbe, Yayoi overcomes her fears and stands to protect them, gaining the power to become Cure Peace. Although she is still afraid of the Akanbe, that fear comes out as an electric attack, which allows her to defeat the Akanbe.

Impressed by her courage whilst standing up to some upperclassmen, Miyuki sees Midorikawa Nao as a potential Pretty Cure candidate. Wanting to get a chance to invite her to join, Miyuki ends up joining Nao to her home, where she meets her large family of siblings. As Akane and Yayoi join them to play some games, Akaoni appears, making Nao and her family miserable and creating a goalnet Akanbe who takes Miyuki as hostage. As Nao becomes determined to protect her family, she gains the power to become Cure March and defeats the Akanbe.

With one more Cure to find, Miyuki decides it should be the student council vice president, Aoki Reika. However, Reika rejects the offer as she is busy preparing for a storytelling event with a neighbouring elementary school as the president is absent with a cold. Miyuki and the others decide to help her out with the event preparations, helping to create some props for the show. However, during the show, a witch from the Bad End Kingdom named Majorina appears and creates a mirror Akanbe which clones itself, causing the Cures to waste their power. When Majorina starts wrecking the puppets for the show, Reika stands up against her and becomes the fifth Cure, Cure Beauty, figuring out who the real Akanbe is and defeating it. After finishing up the show, Reika accepts the offer of becoming a Cure.

The gang is visited by Candy's older brother, Pop, who takes them to magical library Miyuki discovered before. He then proceeds to explain about his homeland, Märchenland, was invaded by Pierrot, who stole the Cure Decors, sealing them away in the noses used to summon Akanbe. Using the last of her strength, the Queen of Marchenland sealed Pierrot away, requiring the Cure Decors to be restored. As Miyuki randomly decides that the team needs a catchphrase, Majorina appears to cause trouble in the park. As the girls warp to the location, Miyuki accidentally sent to the South Pole when her mind focuses on penguins. After Pop helps to bring her back, Miyuki decides to dub her team the Smile PreCure. As Majorina brings out a Drink Can Akanbe, Pop transforms into a giant can crusher to help the Cures defeat the Akanbe. Afterwards, Pop returns to Märchenland, leaving behind the Decor Décor to store the Cure Decors.

Realising more privacy is needed when discussing Pretty Cure matters, Miyuki suggests to the others that they need a secret hideout. Feeling the mysterious library doesn't fit their tastes, each of the girls suggests their own ideas for a hideout, each turning out to have huge flaws. Miyuki remembers a hideout she went to during her childhood, only to find two girls have since made it into their own secret base. Just then, Wolfurun appears and creates a Tree Akanbe, but the Cures manage to defeat it. Afterwards, they come to realise the mysterious library is the most suitable place after all. With some help from the Star Decor, they soon turn the place into the perfect secret base.

On their way to school, Miyuki and Candy find a pair of strange rings Majorina lost which attach themselves to them, causing them to switch bodies. Unable to figure out how to get the rings off, Candy has to fill in for Miyuki during classes, causing chaos with her childlike behaviour. After Miyuki scolds her for embarrassing her, Candy runs off and is targeted by Majorina, who creates an Akanbe from a playground ride which proves too fast for the other Cures to handle. As Candy stands to defend Miyuki, she apologises and manages to become "Cure Candy", proving to be the perfect size to defeat the Akanbe whilst the others manage to retrieve a potion from Majorina to remove the rings and return Miyuki and Candy back to normal.

On April Fools' Day, Yayoi makes up a lie that she is being transferred to another school the next day. However, Miyuki takes it seriously and spreads the rumor to the others, with Yayoi finding herself unable to tell them it was a lie. The lie soon ends up escalating across the whole class, who throw a farewell party for Yayoi, making it harder for her to tell the truth out of fear of losing her friends. Just then, Akaoni appears and creates an Roller Akanbe, using lies to throw off the Cures' guards and bringing Yayoi's lie to light. After some encouragement from Miyuki, Yayoi comes clean about her lie to the relief of the others before defeating the Akanbe. After Yayoi apologises to the rest of the class, the other girls play a little prank on her.

When her father ends up injuring his back, Akane decides to help run her family's okonomiyaki restaurant. However, she becomes a bit concerned that her okonomiyaki isn't as good as her father's and enlists the help of the other girls to perfect the recipe. As Akane struggles to find a recipe she is happy with, Wolfurun appears and creates a Sauce Akanbe to fight the Cures whilst scarfing down okonomiyaki. Akane soon comes to realise the secret behind okonomiyaki's taste is the feelings put into it and manages to defeat the Akanbe, soon finding her own okonomiyaki to be a hit with the customers.

The girls are discussing their upcoming class trip and how much fun they are going to have. Candy wants to come too but Miyuki says she should stay home and watch the house. Later in class Reika is trying to get everyone's attention to start planning but no one pays attention so Candy steps in and yells. Candy is quickly hidden and Reika gets their attention. Because of everything that's happened Candy feels like she's useless and runs away only to be captured by Wolfurun which makes it worse. Wolfurun then finds the girls and calls out a new type of Akanbe, which has a blue nose. The Cures struggle with this new monster because their normal attacks don't work on it. Meanwhile Candy gets free and catches up and somehow unleashes a new power called "Rainbow Healing" which helps defeat the monster.

Miyuki is excited about the class trip but she's having a big run of bad luck. First candy eats all her nacks then she falls into the fish pond at the Golden Pavilion and has to wear her gym clothes. Then she gets a bad luck fortune, gets lost with her friends and damages a souvenir ment for her mom. Later back at the hotel she accidentally dumps a teapot on the teacher that gets knocked off during a pillow fight. The next day during a trip to the old part of town Akaoni shows up and turns the bad luck fortune into an Akanbe which Happy tries to purify but looses her smile pact. Miyuki serces for it in the river but feels really bad but the other grils reassure her that they still had fun despite the bad luck. The do raibow healing and drive off Akaoni. Afterwords Miyuki's luck starts to change.

Miyuki, Yayoi and Candy gets separated from the others, and are lost in Osaka.

Miyuki's Mother's Day present is to help her mum out with household chores.

Reika is troubled when she cannot answer the question "Why do you study?" posed by the other girls.

Akane gets the other girls to take part in a manzai contest.

The girls are chosen to compete in an inter-class relay race.