Sakura Kinomoto is the youngest of two, her older sibling being her brother Touya. The two live with their father, Fujitaka Kinomoto, an archeology professor at a university. Sakura's mother, Nadeshiko, died when Sakura was only three from an unknown illness. Despite this, Sakura grew up a happy, unselfish child and, by the age of ten, she had actually become extremely popular and athletic.
However one day, in her father's library in the basement, Sakura uncovered a dusty old book entitled "The Clow". It was locked tight, but Sakura managed to open the book just by touching it. Looking inside, she saw that it was supposed to contain something, despite there being nothing in it. Suddenly, a creature, which looked like a small yellow stuffed animal with cute little angel wings flew out of the book.
He introduced himself as Keroberos, the guardian of the seal of the Clow Cards. Sakura threw many questions at him during the coming minutes. Kero explained that the cards were alive and that each one possessed its own form, personality and magical ability; and that Sakura would have to use her latent magical abilities to seal the spirits back into cards before their seals were broken and evil befell the world. Using the little magic he had left, Kero summoned the Key of Clow, and bestowed its magical abilities upon Sakura.
Sakura's first two Clow Card captures were easy, as the cards were gentle and totally non-aggressive (The Wood card and the Windy card). However, the third card she had to seal was extremely aggressive and Sakura had to use the Windy card to form a whirlwind around it before she was able to seal the card away. Her adventure was caught on tape by her best friend (later revealed second cousin) Tomoyo Diadouji.
Sakura met Tomoyo at school the next day, after meeting Yukito, her older brother's best friend. Although Yukito was a lot older then Sakura, she still had feelings for him.
That day at school, both Sakura and Yukito's classes were doing sports outside, when a massive gust of wind caused the ground to shake and caused the plants to fly out of the ground. Sakura could barely make out the figure of a massive bird, and her first thought was... it was a Clow Card.
That night, Sakura, Tomoyo and Kero sneaked into the school and looked around for the card. It appeared, and Kero was able to confirm its name: the Fly Card. Sakura instinctively used Windy against it, but as Fly was created under the element of wind, it simply absorbed the attack and blasted it back out, forcing Sakura and the others to flee.
Staying at home for the rest of the night, Sakura decided it was best if she got some sleep. During her sleep, she had a strange dream, where she saw the fly card bleeding and in pain... and the next day, remembering her dream, Sakura was ready with a plan.
Again, Kero and Sakura encountered the Fly card and it attacked by blowing Sakura into the sky. She used the Wood card to create a forest she could land gently upon, before summoning the newly-captured Jump card, which gave her ankle wings, allowing her to jump amazing heights and wrap her arms around the Fly card.
"It's okay" she said, comfortingly.
The Fly card shrunk to the size of a normal bird, and Sakura was able to return it to its card form. While Sakura and Tomoyo celebrated the capture, Kero hung heavily in thought, thinking that maybe Sakura had a lot more magical potential then he thought, as she was able to have precise precognitive dreams. Sakura was able to heal Fly by placing it back in The Clow. After Kero told her to use it, Sakura places her staff on the card. On the end of her staff, massive wings formed, granting her the ability to fly.
A few days later, Sakura and her classmates were looking forward to swimming at school. But Sakura's friend Chiaru mentioned something that had happened with an older student at the school. Something had grabbed her leg and pulled her down, despite nobody else being in the pool at the time. Sakura, having a fear of anything she didn't understand, freaked out.
Sakura later mentioned the incident to Kero, who said the strange happenings were probably the doings of the Watery card. He explained that the creator of the Clow Cards known as Clow Reed had made four elemental cards: Windy, Watery, Firey and Earthy. These cards were stronger then the others and that Sakura would have trouble with Watery because, unlike Wood or Windy, Watery was extremely aggressive and destructive and none of the cards she had would be able to combat it.
Sakura did her best to think of a solution to the problem, but had little luck. Surprisingly, the one who provided her with the answer was Yukito, when he called her and asked if she wanted to go with him to get ice cream. She declined, and ran back to Kero to prepare a plan.
Sakura later met Tomoyo at their old school, where Tomoyo told Sakura that "everything was ready".
Sakura called up Watery, which transformed into a water dragon and went straight for her. Sakura had to use Fly to evade Watery's attacks. Eventually leading Watery to an area which led into the school freezer, Sakura used Windy to force it in and, as Watery froze, Sakura was able to freeze it right away.
Sakura seemed to dedicate the capturing of the card to her love, Yukito, for supplying her with the way to capture it.
The next card appeared to Sakura's friend Naoko, who was coming home late from her piano lesson. Every day, she would walk home through Penguin Park and never had any problems... until a luminous glow in the pond formed an image of a ghost, which caused her to run away screaming.
Telling her classmates about the ordeal the next day, Sakura's fear of unknown things kicked in and she refused to ever go near the pond. But later on, she remembered she had to walk home but presumed she would be okay as long as she was with Tomoyo and her other friends. However, things didn't turn out how she expected, and she ended up seeing the outline of a woman but was confused when, the next day... everyone had ended up seeing something different.
She told Kero, but he said that he wasn't certain about what card it could be, and said that they should go and investigate. Going again with Tomoyo, Sakura used Fly to reach the middle of the lake and the image appeared again... this time forming the shape... of her mother, who, along with Sakura, sank to the bottom on the lake.
Sakura began to drown, so Kero tried to fly in and save her, but was blown away by a magical force field created from what Sakura felt about seeing her mother again. Despite this, Yukito happened to be passing by, and managed to jump through the force field and save Sakura. He had no idea anything magical was going on but, when Sakura woke up, he told her that if it really was her mother in the lake, that Sakura should think about whether she would put her in so much danger.
Going back there again that night, Sakura was again pulled down by her mother but remembered what Yukito said and broke free. Her mother's image went blurry, and a kaleidoscope pattern covered her entire body. Kero recognized the pattern, and Sakura sealed the card away. It turned out to be the Illusion card, with the ability to show what is in someone's heart. The next day, while Sakura was leaving for school, Toya could see his mother's spirit hovering over her. Nadeshiko looked at him.
"At first, I was a little worried" she said, "But now I'm sure everything's going to be alright."
The second series begins at Sakura's school where Sakura takes part in a lot of the contests which includes baton throwing and gymnastics. Her father, Fujitaka, arrives and says he is going to take part in the parent's race. Then Tomoyo's mother appears and greets Sakura, smiling, and then looks up at Fujitaka, and screams...
Turns out that Sakura's mother Nadeshiko and Tomoyo's mother (Sonomi) were cousins, and Fujitaka was their teacher. Sonomi hated Fujitaka because Nadeshiko was only 16 when the two married and had kids, and she thought Fujitaka stole Nadeshiko away from her.
Meanwhile, Sakura had finished her events and was sitting down to eat with Tomoyo, who noticed a load of cherry blossoms were falling, despite there being no trees. After a while, everybody was knee-high in petals but, despite this, the parent race still went on with Sonomi determined to beat Fujitaka.
After a while, barely anything was visible under the blossoms (Sonomi and Fujitaka still raced) and Sakura and Tomoyo knew by know that a Clow Card was on the loose. They flew up and saw it on the school roof. A beautiful young woman with her hair tied up in two cones and a long, frilly pink dress.
Sakura went to seal her away, but the card began dancing with her. Tomoyo phoned Kero, who said it was the Flower card and it wasn't aggressive, it just loved to make people smile. Sakura sealed Flower away and was gobsmacked when Kero said that it had no battle uses, instead it could materialize any flower in the world.
Down below, Fujitaka had ended up winning the race and Sonomi was telling him about all her regrets and Nadeshiko's life... so Sakura used the newly caught Flower card to give each of them a nadeshiko flower. Sonomi begins crying, and Fujitaka comforts them, and another chapter in Sakura's magical adventure came to an end.
Time passed, and Winter was coming. A new boy attended Sakura's class, Syaoran Li from Hong Kong. At break-time, he attacked Sakura because of the Clow Cards, claiming he was a descendant of Clow Reed and deserved them. Luckily, Touya came and stopped Li.
Later, Sakura went with Tomoyo and her friend Rika to the shops. Rika laid her eyes upon a beautifully decorated brooch shaped like a sword, and bought it.
Later on at home, Rika knocked at Sakura's door. Sakura was alone and tried talking to Rika, who wouldn't reply. Her eyes were dazed, and she pulled off the brooch which transformed into the Sword card. Rika went at Sakura, who barely dodged near-fatal attacks from the mind-controlled Rika. Sakura used the apparently useless-in-combat Flower card to create a defensive barrier around herself, giving her time to get out of the house.
Li appeared, and tried to attack Rika with his sword. Sakura used the Jump card and then pulled Li out of the way, saying she would not allow any harm to come to Rika, especially as she had no control over her actions. Kero then said that Rika would only have to stop touching the sword for a few seconds for it to be sealed away. Sakura pulled out a card, and had an idea.
"Illusion card, project the image of the one in her heart!", Sakura exclaims.
Sakura then used the Illusion card, and it revealed Rika loved her teacher, Terada-sensei. Sakura was shocked, but was able to knock the sword out of Rika's hand. Rika fainted, and Sakura sealed away the Sword card. After this, Sakura didn't do much card capturing for a while though she did happen to seal away the Thunder card.
In the shop where her brother was working, Sakura witnessed a shadow become solid and knock a shelf over onto a girl, who Touya saved. Li was standing at the door to the shop, and told Sakura it was a Clow Card.
Later, Sakura, Kero and Tomoyo went back to the area, where Kero told Sakura that as she had collected more cards, her magic should have developed so she could sense cards in a local area. Kero was proven right when Sakura was able to dodge an attack from what Kero said was the Shadow card. Sakura used Windy to clear a bit of space, when Li appeared. He told her Shadow could touch them, but they couldn't touch Shadow. He used a weak thunder spell to create some light which caused the shadows to disappear, and also said that Shadow dissipated under light.
This gave Sakura an idea, and she used the Thunder card to ignite lamp posts around the Shadow, so that its main body appeared. When it did, she used the Sword card to cut it, because the Sword card is the only thing that can physically hurt Shadow. Sakura sealed Shadow back into its card form.
However, the posts she had ignited had ended up causing a massive fire, and people in nearby buildings were beginning to wake up, screaming. Sakura quickly used Watery to extinguish the flames and then flew away, into the night.