Prologue

Early May—

During high school——no, right before the one and only, once in a lifetime school trip of high school, Ikuse Tobio was necessarily absent.

Yesterday, his physical condition had been poor. He had a fever that would not go down and his body was devoid of strength. His head was in a daze, and he was also unsteady on his feet.

Although it was the beginning of Golden Week, this was no reason to be careless….he was still afflicted with the sudden illness. The doctor had also prescribed that he rest.

“So then, since I’ll be buying souvenirs, you’re going to obediently lie down?”

Saying so while standing smiling at the front door was a semi-longhaired girl. She’s a classmate of Tobio in the second year of the same high school. She’s also his childhood friend, Toujou Sae. Her smile was mischievous.

“…Aah.”

Tobio responded while pouting through the mask.

She had come to check on Tobio’s condition prior to departing. From Tobio’s perspective, there was no choice but to disagreeable.

The itinerary of the trip was a period of ten days on luxury liner cruise touring the Hawaiian Islands.

For Tobio, it was supposed to be his first trip overseas. As a student at the time, there was no way he wouldn’t have enjoyed it. With how very heavy his body felt, he was quite bitter.

Sae poked Tobio’s forehead which had displayed a sullen look.

“I can go anytime once we become adults. Then we’ll go together, so please try to endure this time.”

“……How stupid. I want to go today. And anyways, you say you’ll accompany me, but you’re just going to have me treat you, right?”

“You got me.”

Sae laughed and chuckled. Tobio exhaled, rubbing his poked forehead.

After she finished teasing Tobio, Sae picked up her bag.

“Well it’s about time, I’m sorry to say.”

“Ah, wait a minute.”

Tobio calls Sae back as he reaches into his pants pocket, and takes out a string of beads.

He places it on Sae’s left wrist.

“My late Baa-chan¹, she’d always make sure I’d wear this when I travelled. Since I’m unable to go, I’d like you to take it and be protected on the trip.”

Sae looks at the beads, and thankfully rubbed them with her hand.

“Thank you.”

“Um….that’s, how I should put it, I want you to take care of yourself.”

Saying so, Tobio’s face, already red with fever, got even redder.

“What?”

“Uh…….you know diseases and such, viruses and such.”

“That’s probably what you have.”

Receiving such a sarcastic reply, Tobio’s mouth bent into the shape of “へ” under the mask.

As she opened the front door, Sae took one final look back to say.

“I’ll be going now.”

She gave a slightly lonely smile, and departed.

Four days after his fellow students had left——.

They had travelled by airplane from Narita to Honolulu. From there, they boarded the “Heavenly of Aloha” at the harbor, and by now it should be the arriving at the Hawaiian Island of Kauai.

To imagine his fellow students smacking their lips after partaking of the luxury liner’s cuisine, touring each and every island, and thoroughly enjoying the cultural exchange was likely to make him feel bitter.

With his physical condition having recovered little by little by late morning, Tobio was preparing for brunch.

Tobio does not remember his parents’ faces.

By the time he was physically and psychologically aware, his parents were gone, and thus, until junior high school, he had been brought up by his grandmother. His grandmother had also died around the time he became a junior high school student. Since then, he had been living on nothing but the inheritance his parents and grandmother had left behind. Due to the maid acquainted with his grandmother had been asked to assist in his daily life, it was possible for a high school student to purchase all the necessities without any particular inconvenience.

Tentatively, he had no memory of any relatives or guardians——someone who could have become his protector, so there wasn’t anyone to contact, and so it was that he had come to lay hand to the inheritance.

Therefore, after becoming a high school student, he now lives alone in a one room flat. It was relief for him that Sae would come over to make dinner.

Though even without going as far to have someone prepare meal and the like that morning, Tobio did make fried eggs, which he began to eat along with some bread.

His fellow students would probably have already finished eating an elegant breakfast. Thinking like that, his breakfast seems sorrowful.

He moved to the TV, and while gazing at it in a daze, he nibbled at his bread.

‘The search is still ongoing in the case of the missing persons——‘

Tobio gnawed silently at the bread while watching the TV without any particular interest.

‘Students and teacher of Ryoukuu High School while on a school trip had safely boarded——‘

What……?

Tobio heard the name of a familiar high school, suddenly gluing his attention to the TV.

The TV was showing a maritime video that was taken from the air. As if out of a movie, there was the majority of a luxury liner’s hull sinking into the sea while giving off smoke.

He wondered if he could not have misheard something. This should be impossible! Extraordinary things such as this, they’re not supposed to happen to you!

Tobio’s heart was repeatedly attacked as the brutally ruthless TV’s subtitles displayed “Mysterious shipwreck of the Heavenly of Aloha”.

With the name of passenger ship confirmed, Tobio opened his eyes wide in shock. A chill travelled down his spine. He began breathing violently and his heart rate accelerated, and he noticed his heart pounding.

Tobio checked the information on the Web through his cell phone.

He checked the news written in one article. Its contents made Tobio’s body quiver.

‘Luxury Liner, Marine Accident!’

‘Nightmare on the School Trip!’

‘Status of the 233 high school students on board unknown——‘

‘Hopeless for missing persons——‘

The name of the high school, Ryoukuu High School——.

And Tobio, thought of his childhood friend Sae who he’d gone through high school with.

—— I’ll be going now.

Within Tobio, the last words said by his childhood friend reemerges. Sae, who had given him that slightly lonely looking look while smiling. ……There was something about that combination that signified how hopeless things were.

“……Sae.”

Completely drained, Tobio sat down right where he was.

That day, Ikuse Tobio lost 233 of his fellow students, including his childhood friend Toujou Sae——.

1. grandmother