Kaedehara Kazuha was Seaman Apprentice for the Japanese battleship Yamato, he was assigned to the battleship Anti-Aircraft Division unit, and his childhood friend Yoimiya Naganohara hugged him with her tears

Yoimiya: be safe, Kazuha.
Kazuha: I will.

Then he went to the boat as the sailors depart and gave their farewell to their loved ones.

Yoimiya: Good Luck!

He waves at her as the boats arrived at Yamato. She's ready to depart toward her destiny.

Yamato along with her escort ships are sailing towards Okinawa Islands (Watatsumi Island). Yoimiya prayed for his return.

7 Years Earlier

In October 1944, in Kure, Hiroshima, Japan (Inazuma). Yamato is under repairs after its disastrous defeat on Leyte Gulf. Kazuha has some time on his day off, He saw her fireworks shop. It turned out to be the famous Naganohara where Yoimiya lived.

Yoimiya: Kazuha! You're back!
Kazuha: Hey, Yoimiya.
Yoimiya: C'mon in.

She said with her cheerful face. She gave him tea that he liked. He explained the situation about what happened

Yoimiya: Damn, It must be pretty hard.
Kazuha: Yeah. But at least everyone is okay.
Yoimiya: They sure do. Wanna hang out like the old times?
Kazuha: Sure.

With that, they started hanging out, they talked about how their life. Kazuha knew Yoimiya since childhood for 15 years. They have their dreams, Kazuha wants to become Seaman Apprentice and Yoimiya wants to become a Fireworks Shop owner. They still hang out.

In January, 1945.

Fireworks Festival participated by Yoimiya and Kazuha to enjoy their festival in Kure.

Kazuha: Thanks for preparing the Festival.
Yoimiya: You're welcome. Anything for a good friend like me.

They watched the fireworks together as he hold her hand. Yoimiya blushed a bit.

Yoimiya: Kazuha, we're not there yet.
Kazuha: Oh right sorry.

That's right Kazuha just fell in love with her since childhood as he tries to show his affection but he was friend zoned anyway. He was hurt a bit. Unbeknownst to Kazuha, Yoimiya secretly falls in love with him.

2 years passed, and it was March 1945. The Americans (Mondstadt) launched an air attack on Kure. Imperial Soldiers evacuated the people of Kure set up by the Imperial Japanese Military Police (Tenyrou Commission) and their general: Kujou Sara.

Sara: Everyone, into the bunker! Now!

Kazuha and Yoimiya made it to the bunker. Yoimiya hugs him as she was scared, He comforts her by hugging her. After their bombing run was over, they went back to their homes. Kazuha has the courage to confess his feelings to her.

Kazuha: Yoimiya.
Yoimiya: Yes?
Kazuha: I have something to tell you.
Yoimiya: Okay.
Kazuha: I just wanna know that you're a bright woman like the light of the moon is not its own, and so is my smile not my own. 
Yoimiya: What are you talking about Kazuha?

He kneeled down to her, she looked flustered and confused. Her smile is as bright as the sun, but can one keep all the light of the sun to one's self? 

Kazuha: I love you Yoimiya, will you continue to light my way till the day our brief moment ends?
Yoimiya: K-Kazuha? It's not nice to joke about this kind of stuff. I am too carefree, and I don't think I will make a good wife. I always thought that other woman is far more suitable for you.

I hold her hand.

Kazuha: So what? Yoimiya, the one that I love is you. Even if all she said is true, I love those parts of her too.  
Yoimiya: I'm sorry but I need time to think about it. Can we stay friends for a while, okay? *smiles*

And so she turned away from him. That was a final straw for him

Kazuha (thoughts): So, this feels like being rejected.

Since then, she has always been avoiding him. It has been a week since. he accidentally saw her talking with Thoma. He has saw them from a distance as they laughed and she blushed. He could not hear their conversation, but he realized that he already have his answers. It was not that he did not understand, he just did not want to admit it.

Even before he was here, they had always been together. He is tall, dependable, talkative. They make a perfect pair. But he did not want to leave without saying anything. At the last minute before his departure, he went to her house, he saw her shadow but she still hid from him.  At this point, everything was already too late.

It was April 6th, 1945. Yamato was fully repaired and ready to sail. The sailors bid farewell to their loved ones before getting on the boats.

Yoimiya hugged him for the final time

Yoimiya: be safe, Kazuha.
Kazuha: I will.

Then he went to the boat while hiding his broken heart and his sadness as the sailors depart and gave their farewell to their loved ones.

Yoimiya: Good Luck!

He waves at her as the boats arrived at Yamato. She's ready to depart toward her destiny. Unbeknownst to Yoimiya, Kazuha wanted to be alone to avoid her.

Yamato along with her escort ships are sailing towards Okinawa Islands (Watatsumi Island). Yoimiya prayed for his return. But unfortunately, her prayers didn't answer.

It was April 7th, 1945.

Yamato with full magazines and its sortied fleet with one light cruiser and eight destroyers are on a suicide mission. A Convoy of ten ships led by Yamato is attacked by 400 American planes.

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(Watch at IJN Yamato part)

April 8, 1945
Kure, Hiroshima, Japan, 9:13 am

Yoimiya is doing her routine while hoping that he will return. Then there was a knock on the door. She goes to the door and opened it revealing Officers

Yoimiya: Hello, how may I help you?
Officer: Ma'am I hate to say this, but we have some bad news.

Then this worries her about the news about Yamato and her friend.

Yoimiya: What kind of bad news, sir?

Officer sighs and finally tells her that will break her heart.

Officer: Yesterday, Yamato was attacked and sunk by enemy aircraft, along with her men.

Yoimiya got horrified that the battleship Yamato sunk in battle and was destroyed.

Yoimiya: Kazuha, was he there too? Is he okay?!
Officer: I'm afraid ma'am, He was, but we do not know if he's alive or not. I'm sorry ma'am.

Then she kneeled to the ground as she screamed in despair.

Yoimiya: NNOOOOOOO!

It hits her heart so much.

Yoimiya (thoughts): This can't be happening, He's gone. This is all my fault.

She cried in despair, knowing it was too late to confess her feelings to him.

On April 9th, Yoimiya decides to have a day off to clear her head as she went to her room to read Kazuha's Letter given by the officer. She opens and reads his last letter.

Yoimiya, If you are reading this letter, I'm already gone. I know you have a relationship with Thoma, and I understand that. I bet it's too late for me. Yoimiya, I will always love you no matter what. But please enjoy your life with Thoma

- Kazuha

She covered her mouth as she cries so loud as Thoma tries to comfort her. She finally realized Everyday that passed made her more and more just how much he meant to her.

Months passed after Yamato has sunk in the battle, and Japan surrendered to the United States as they signed a peace treaty. They send food supplies to Japanese Civilians. Yoimiya looked at the sunset.

Yoimiya: Kazuha, you're such an idiot. Why did you leave me?

She starts to have flashbacks of Kazuha's face and his smile.

Kazuha: You're my good friend. I know you can do it. I believe in you. *smiles*

Then the day of his confession.

Kazuha: I love you, Yoimiya, will you continue to light my way till the day our brief moment ends?

The flashback ends with her.

She finally smiles with tears in her eyes.

Yoimiya: I love you too. *sobs*

She looked down as she kept weeping. Knowing the man she loved was gone forever. She used to have suicidal thoughts but he wanted her to move on.

Yoimiya: Kazuha, I may be too late for saying this but, I will always love you, Kaedehara Kazuha.
???: I love you too, Yoimiya Naganohara.

She turned around to see Kazuha again.

Kazuha: I'm glad.
Yoimiya: Kazuha!

She hugged him.

Kazuha: Hey, you missed me?
Yoimiya: You're such an idiot! Why did you scare me like that? BAKA!
Kazuha: I'm sorry.

She kissed him.

Kazuha: I thought you were going out with Thoma?
Yoimiya: Thoma? Nooo. He just helped me to sort out my feelings for you.
Kazuha: Oh.
Yoimiya: Please Take care of me.
Kazuha: Ok.

They hugged each other knowing they finally know they truly loved each other.

3 years later

Kazuha and Yoimiya got married and have their children. They looked at the view of the sunset and saw the ghost of Yamato, He made a final salute to their fallen sailors who fought to the bitter end before they disappeared into the rising sun.

Yoimiya: You ready to go?
Kazuha: Sure thing, darling.

They went back to their house, and they lived happily ever after.

The End