A young man opened his bag and took out a watertight capsule. After a few moments of silent contemplation for the package in his hands, he sent it into the ocean.

"This is technically water pollution, you know."

"Shut up, Hagita."

The group of friends kept their eyes on the capsule as it drifted away into the distance.

"Creating another timeline is one thing. But finding a specific one is totally different. We don't even know how many parallel worlds there are."

"Shut up, Hagita!"

"I knew it was a long shot," the dark-haired man admitted. "But I still wanted to try. Though it would take a miracle to actually work..."

"But we already got one miracle," Naho said with a smile. "If we can do it once, we can do it again."

Kakeru nodded. "Yeah."

.

Somewhere else, in a place that was both far away and at the same time very similar, Suwa Naho checked her mailbox. There was only a single envelope on that bright, clear morning. It wasn't until she brought the envelope back inside her home that she noticed how it was addressed. It simply read: "To Takamiya Naho."

She blinked. There was a stamp, and it was obviously meant for her, but she couldn't understand how it was delivered without an address, or why the sender wouldn't write one. What's more, she hadn't used the name Takamiya in a while.

Actually, that's not true. Naho called herself by her maiden name quite recently - when she wrote a letter to her past self. She and her friends had all written letters and tried to send them back in time.

Naho got an intense feeling of deja vu. She flipped the envelope around to see the return name on the back. "Naruse Kakeru."

Naho quickly opened the envelope and began to read.

.

This letter may never reach the right destination, though I pray it does. It won't make any sense if read by the wrong person. It sounds crazy, but I'm trying to send this letter from a parallel world.

If it does work, this letter should be delivered to the home of Takamiya Naho in her 26th year. But not just any Naho. I want this letter sent to the world where Naho's friend Naruse Kakeru died on Feb 15 2013 - And the world where Naho and her friends sent letters 10 years into the past to try and prevent that death.

Takamiya Naho, Suwa Hiroto, Murasaka Azusa, Chino Takako, Hagita Saku, did this letter reach you? Are you the ones reading this?

It's me, Kakeru. I'm alive.

I believe this letter can reach you somehow, because your letters were able to reach me. I'm writing because I want to let you know your letters really did arrive in the past. You created a parallel world where I survived. That must sound unbelievable, but then again if you really thought it was impossible you wouldn't have tried it in the first place. You sent a lot of advice to your past selves - especially you, Naho. More than ten whole pages of overthinking. That's just like you.

But I'm afraid your advice only half-worked. You warned your past selves not to invite me on the day of the entrance ceremony, but I went with you anyway. And my mom still died. Don't blame yourselves, though. I was the one who broke my promise to her. If only that one day changed, there probably wouldn't have been any need for anything else. Even so, the letters weren't for nothing. We couldn't save my mom, but you did save me.

Although, I'm still dead in your world, aren't I? You'll never see me again. And for that I'm sorry. I'm truly very sorry.

The real reason I'm writing this is because I want to erase your regrets. Even if I can't come back in your world, I thought that if you knew your plan worked - that you created another world where I was alive and well - it might give you at least a tiny bit of relief.

The Kakeru that you all knew - he was from a different world where different things happened. I can't be sure exactly what he was thinking. But he probably felt that dying was the only way to apologize to mom. That it was the only way for his sins to be forgiven. He probably hated himself for not being stronger. So sad and angry that he really couldn't think straight at all.

But he was wrong. I was wrong.

I finally understand now. Dying doesn't make things better. It just makes them stop. And it makes things worse for the people you leave behind. I should have focused on trying to leave something good in the world. I'm so sorry for leaving you. I wish I was strong enough to save myself.

Your letters said you were sorry for not saving me and you asked me to forgive you, but there's really nothing to forgive. None of you did anything wrong. My mind was stuck in a bad place, and I didn't know how to ask for help. I wouldn't let you help me. I'm sorry.

That first year after my mom died was so hard. The things I thought during that time... It was a terrible mindset to be in. I try not to think about it. A part of me wants to blot it out of my memory completely. But at the same time, I feel like I need to remember in order to learn from it and do better.

It's been ten years since my mom's death, and even now I don't have all the answers. It's not always easy. I still have bad days. I still regret losing her and that feeling will probably never go away completely.

Even so, I've finally reached the point where I can honestly say I want to live. Not just scared of dying, but really want to be alive.

Thank you for saving me. It's because of you - both the versions of you in my world, and you, who sent the letters. And even though your Kakeru lost his battle with depression in the end, I'm certain that he was happy to know you. You were all wonderful friends.

One more thing: Could you share this letter with my grandma too? The idea of parallel worlds might be hard for her to believe, but please try to explain everything to her.

Grandma? I'm sorry. Back then I was so wrapped up in my own feelings I forgot that you were suffering too from mom's death. I was wrong to think another death would make things better. I'm sorry for leaving you. But please, try to be happy. I've realized that my own life helps keep my mom's memory alive. So instead of being sad, try to keep both our memories alive. And know that somewhere, far away, I survived and I'm living a good, happy life. I love you.

Grandma, and all my friends, thank you. I can't thank you enough for saving me. We will never meet again, but I want you to know how much I love you all. I hope you stay close friends and keep smiling forever. Please let go of your regrets.

I want to thank you all from the bottom of my heart. I wish you all the happiness your world has to offer.

Naruse Kakeru, age 26.

.

There was something else in the envelope. It was a photograph. Naho took it out and saw the date scribbled on the back. 2022/4/23. She flipped it over. Naho recognized the scene immediately.

It was her and her friends standing on Mount Koubou, with the orange-dyed sky and pink cherry blossoms. But a sixth person was there - Kakeru. It was a version of Kakeru that Naho had never seen before - not a child or a teenager, but a Kakeru who had lived long enough to grow up into an adult.

And he was smiling.

"Ha... ha..."

Her breath was shaky. She blinked, and felt tears run down her face.

"Naho?"

Hiroto stood in the doorway, watching her with concern. Naho was crying, but she was smiling.

"What is it?"

She didn't speak. She only handed the letter and the photograph to him. She gave him a silent moment to read it, watching his expression change. Confused, then surprised, then happy.

"We did it, Hiroto... We saved Kakeru."

.

"They received it," Hiroto spoke up, watching the ocean. "I'm sure they did."

"Well, even if they didn't, the next letter is the one that really counts, right?" Takako said.

"Uh-huh." Kakeru reached into his bag and pulled out a second watertight capsule. "That letter was to give thanks, and to erase their regrets... This one is for saving a life."

.

Fifteen-year-old Kakeru slammed his bedroom door shut - loudly.

He had had another fight with his mother. Now he leaned his back against the door and slumped to the floor.

"Dammit, mom... Just once, can't you-"

Kakeru stopped his mumbling because he noticed something on his bed. It was a letter for him that came in today's mail. He tossed it on his bed earlier and forgot about it.

He walked over and picked it up, turning it over in his hands. It was addressed to "Naruse Kakeru"... but strangely, the return name on the back was also "Naruse Kakeru". It was sent by someone with his same name?

He opened the letter up and started reading. He recognized his own handwriting.

To Kakeru:

This letter is from your 26-year-old future self. I'm writing this from 11 years in the future. I know that sounds hard to believe, but please bear with me and keep reading till the end. I have something very important to ask you. There's a regret of mine I want you to erase.

I want you to save mom.

.

To the people reading this: If you or someone you know is waiting for a sign that you should keep living, this is it. The Suicide Prevention Lifeline is 1-800-273-8255. That hotline exists for a reason. It gets better.