Arrietty Clock had to move away from the house she had lived in for her entire life until she was fourteen years old. Her father, Pod, and her mother, Homily, went with her. So did Spiller, who did not speak very much, though he was not related by blood or marriage to the Clock family.

All four of them were Borrowers. That meant they were all naturally tiny when compared to a human, with Arrietty being about four inches tall, and the other three were not much taller. They had to keep their existence a complete secret from "human beans," which was what they called normal sized humans due to a misinterpretation of the phrase "human beings."

Borrowers who were seen by humans were often never heard of again, so they had to move out as soon as they could. Most Borrowers never considered the possibility that a human bean and a Borrower could be friends. However, that is what happened, as Arrietty was seen by a human boy named Sho.

Sho was staying over at the house the Clock family lived in, and it was going to last a little over a week before he would undergo surgery to fix his weak heart. For most of that time, he feared that the surgery would lead to his death. However, the day before it happened, he had worked up enough courage to face it unafraid.

One night earlier on, the same night that Arrietty was first "borrowing" from the humans, he saw her. She feared for her life, yet that was also the start of her developing feelings for him. She did not get what she came for, but Sho seemed to give it to her anyway on a later day. Her parents thought it was a trap, so she just left it there, and ants came and raided it.

After the ants raided it, she read the note, which said she forgot something. Going against what her parents would want, she climbed to the roof to talk to Sho. She almost let him get a good view of her, as she was hiding behind a leaf, but a hostile crow attacked her and ruined the moment. He may have saved her life, but he did not get a good look at her, as she fled the scene before he could. He was also hiding her from Haru, the maid of the house who was quite immature for a grown woman.

Talking with him made her realize later that she had a crush on him. Maybe it was his sensitive personality. Or maybe it was his looks, which she found handsome.

The encounter with the crow ripped up the sleeves of Arrietty's red dress that she was wearing at the time, though it was neat and turned it into a short sleeved dress when it was long sleeved before. Despite her parents scolding her and telling her never to talk with him again once they found out, she wanted to speak with him more. She went outside to him despite being with Niya, the hostile pet cat of Haru, the maid of the house. They talked a bit before he turned around and got a good look at her. He called her beautiful, and while they continued their conversation, he brought up some darker subjects like mortality, extinction, and how he thought his death would come very soon.

Meanwhile, Haru found Homily due to Sho slipping up and his attempts to help the Clock family. Because Arrietty had good hearing, she could hear her mother screaming despite being a long distance away compared to her size. By the time she had returned to her home, her mom was nowhere to be found, and there was a mess, a clear sign that her mother was kidnapped.

She rushed to get up to the window of the room Sho was staying at and get his attention. After explaining what she thought had happened, he agreed to help her. When he put his hand out in front of her with the palm facing up and the rest of his hand being flat, she knew he wanted her to get on. She got on, and in that moment, she was literally in the palm of his hand. Looking back on that moment later, she realized that she was very fortunate he was a merciful, gentle "giant," as she was at his mercy at that moment. He moved his hand with her near his shoulder, and she got on it. Somehow, she stayed stable despite standing.

They went off in search for Homily, who Sho didn't know the name of, but Haru somehow locked them inside the room from the outside. He decided to go through the window and enter the next room over though its window. Arrietty did her part in opening the window, and they were a great team.

When Sho arrived downstairs with Arrietty, she got off of him, and when Haru was surprised as to how he got out, he hid Arrietty from her view and asked for things to allow him to move in ways to hide her better. She managed to save her mother, but Sho walked in to the terror of Homily. Her daughter convinced her that he was on their side.

Spiller had arrived before then, and he helped them find a new home now that their presence was known. Before Arrietty left, though, she got to talk to Sho one last time, as well as give him her hairpin to remember her with. She hugged one of his fingers, but had to say goodbye.

Little did she know at the time that not only did she have a crush on him, but he had similar feelings for her…

They ended up in a house down the road from where the Clock family once lived. They continued to "borrow" things they needed, and while they were not aware of it, Sho had heard of what had happened.

Two years had passed since the Clock family had to move. Despite her parents wanting her to marry Spiller so their bloodline would continue, Arrietty had more feelings towards Sho, though she did not admit it to anyone else despite the fact that Sho helped rescue Homily. Considering making a diary, she asked her mother, "Mama, can you read?"

"No, I can't."

Pod had walked in, so Arrietty said, "What about you, papa?"

"What are you referring to?"

"Can you read?"

"I never learned how."

Arrietty saw this as an opportunity for her to make a diary, and even if her parents found it, their inability to read would mean that her secrets were safe there. The problem was that she didn't have paper scaled to her, and she didn't need to make one. A bit upset, she gave up on that idea.

She realized that the main reason she would write in it was because of her crush on Sho. She really wanted to talk to him again, but she didn't know where he lived.

That went on for long enough that she became old enough to go out on her own. She decided to dedicate her life to finding him again, as she assumed he survived his surgery and had grown up as well.

Arrietty returned to the house where she was seen by Sho, and it was a long journey. She hoped Sho would come there as well.

When she returned, she saw Haru had gone mad and was rehearsing a rant while wearing a hooded robe. Arrietty, who could hear her rant no matter where in the house she was, wondered how she went mad when she was right in that there really were tiny people living in the house so long ago.

She heard a car enter, so she decided to hide herself while getting a peek. It was Sho, who had grown up as she had hoped. Haru saw him and said, "You… You! You are not welcome here anymore! Leave now! I know what you did! I figured it out!"

The yelling in her voice hurt the tiny girl, or rather, the tiny woman's ears. Sho was accepting and not giving a reaction to the fact that the immature woman had gone mad, as he was preparing to leave. Arrietty saw that this was her best chance to reunite with Sho and confess her feelings. When she was sure that Haru had gone back inside and was not looking, she ran over to him while hiding herself with a leaf.

He recognized her immediately and said, "Arrietty! I heard the house down the road has had a lot of stuff go missing! Did your family go there?"

"Yep!" she replied, and he put his hand out in front of him like he did all those years ago. She remembered what this meant and got on, though this time, she had a notable blush in her face like when he saw her in the bedroom many years prior.

"Is-is something wrong?" Sho asked with worry in his voice. As he was older, his voice was deeper than what it was when they last saw each other.

"Nope. Nothing's wrong," Arrietty replied. She was lying, and she knew it, as she wanted to confess her love to him, but she feared that he would not want their friendship to turn romantic.

"Want to go on my shoulder again?" he asked.

"Sure!" she replied. He brought his hand with her up to the same shoulder she rode before, and she hopped on.

"How did you balance all those years ago on my shoulder while you were standing?" he asked.

"I have great balance and great hearing. I don't think the hearing helps with it, but it might somehow," she replied.

With the tiny woman he met when they were both kids on his shoulder, Sho got back into his car and drove away to his own house, as he no longer lived with his parents.

On the drive there Arrietty said, "I'm pretty sure I'm older than you despite you being so much more massive than me."

"That sounds about right."

After he arrived at the apartment he got for himself, Arrietty said, "I'd like to be in your hand again, Sho."

"O...kay?" he replied.

She went from his shoulder to his hand by going down the length of his arm, and she sat there. She blushed some more and decided that now was her chance. She said, "I know we were friends when we left each other. But as soon as you saw me for the first time, or so I thought before you told me you saw me in the garden, I realized I wanted it to be something more. I-I love you, Sho!"

She closed her eyes and feared rejection, but there was silence. When she opened her eyes, he was blushing as well. He said, "To be honest… I thought the same way about you. If this was a love confession, I accept. Now may I give you a big, warm, and gentle hug, Arrietty?"

"I want to know what that's like." she replied.

He hugged her close to his heart, and she could feel the rhythm of the thumps of his heart, which was now much stronger than it was before. She thought that she could get used to that. After enough time had passed, before she fell asleep, she said, "I think that's enough for now."

He stopped, continuing to hold her in his hand. She said, "How about we kiss?"

He nodded, and they both kissed each other at the same time, with his lips covering her entire face, and both of them blushed even more.