Book:
Is there an ebook available?: yes
Is there an audiobook available?: no (or at least didn’t find)
Is there an all-furigana version available?: yes, but according to natively it’s significantly different
(Optional) Is this book available in Korean?: i’m not sure
Summary - Japanese
小磯健二は憧れの先輩・夏希に「4日間だけフィアンセの振りをして!」と依頼され、長野県の田舎に同行することに。その夜、健二に届いた謎の数列を解いたことで世界が一変し!?
Summary - English
From Anilist: When timid eleventh-grader and math genius Kenji Koiso is asked by older student and secret crush Natsuki to come with her to her family’s Nagano home for a summer job, he agrees without hesitation.
Natsuki’s family, the Jinnouchi clan, dates back to the Muromachi era (1336 to 1573), and they’ve all come together to celebrate the 90th birthday of the spunky matriarch of the family, Sakae. That’s when Kenji discovers his “summer job” is to pretend to be Natsuki’s fiance and dance with her at the birthday celebration.
As Kenji attempts to keep up with Natsuki’s act around her family, he receives a strange math problem on his cell phone which, being a math genius, he can’t resist solving. As it turns out, the solution to the mysterious equation causes Oz, the program that controls nearly every aspect of life to be hacked into, it’s up to Kenji and his new “family” to stop the hacker before it’s too late.
Why are you nominating this book: I read the manga of summer wars as a teen and really enjoyed it, so it has a special place in my heart. I was hoping to read it again, this time as a novel. I personally think the story is fun and quite original.
The only downside is that it’s rated with a difficulty of Level 25(?) and has 351 pages, so I worried it may be harder than expected.