I'll preface this review with some context. And this review will also contain spoilers, so beware.

I started to get into the Miaki Sugaru rabbit hole in a serious manner relatively recently, however, I first got to know his works about 4 years ago when I read the manga adaptation of "Three Days of Happiness", that being "I sold my life for ten thousand yen per year". That manga shook me to my core, positively changing my perspective on life.
⠀⠀ㅤㅤㅤㅤㅤAbout 2 years ago, I then read "Three Days of Happiness", which remains my favorite novel to this day. Granted, I'm not a bookworm so my experience with books as a whole is more limited than I'd like, but I digress.
⠀⠀I'm mentioning all of this, because wanting to read Miaki's work was one of the main reasons behind me starting to learn Japanese, seeing that only 3 Days is published in English. In early 2024, my dad gifted me the physical edition of 「恋する寄生虫」(Parasite in Love), in order to help me with language immersion, but I didn't reach a good enough level of Japanese until December in 2024, taking almost 4 months to finish reading it. Consider that when I read in Japanese, I don't read every single day, and some days I only read a little bit.
⠀⠀This time, I purchased most of Miaki's novels during a recent trip to Japan, and so I began reading 「スターティング・オーヴァー」(Starting Over) about a month ago, in early May.

Starting Over is Miaki's first published novel, and it shows his inexperience in some parts comparing it to his later works. Hell, even the prose in Three Days, which he published a few months later (and his best novel out of the ones I've read so far), has a way higher quality. Does that mean that Starting Over feels like a bad read? Absolutely not. It doesn't reach the potential that Miaki can get to, but the signs are clearly there. It's still a damn good novel.

In Starting Over, the story begins with a nameless 20 year old protagonist who, despite living his best life (having a loving partner, a nice family, and good social life) has his consciousness sent back to when he was 10 years old for an unknown reason. He still retains memories from his "first attempt" (called 「一周目」in Japanese, which literally translates to first lap), so he plans on trying to relive the events he has already been through during the following 10 years of this "second attempt". However, that backfires tremendously.
⠀⠀In middle school, he tries to confess to Tsugumi, a girl who he believes was once his girlfriend, not remembering precisely who it was but instead having memories of her physical appearance and personality, but she rejects him. He also never develops any meaningful friendship, becoming a loner throughout his entire student life. Later on during high school, a guy called Tokiwa shows up and gets together with Tsugumi. That, coupled with the fact that Tokiwa is everything that our MC used to be in his "first attempt", results in our MC's mental state spiraling into a deplorable state. This, in turn, causes him to stalk Tokiwa and get delusional about killing him—his doppelgänger—in order to get together with Tsugumi once again.
⠀⠀MC's family life is not as he remembers either. Instead of having loving and kind parents, they are said to be arguing constantly, resulting in verbal abuse at times. And Honoka, his little sister, is not the cheerful and fun girl he used to love, but instead an awkward and introverted bookworm who would rather spend her time at the library instead of practicing sports. The changes in his family encourage our MC to move out during his time at University, moving to a tiny apartment instead where, in time, he becomes a shut-in who skips classes.
⠀⠀Honoka is, from my perspective, the pivotal character in this novel. One night, she shows up at MC's doorstep, explaining that she ran away from home. Up until that moment, MC had distanced himself from her due to not being able to form a genuine bond, as he was always thinking about who she used to be in the "first attempt", and not about who she now was this time. He ended up caving in though, despite his initial resistance due to the whole situation being bothersome, so he lets her stay with him.
⠀⠀It was then when something changes inside MC. Slowly, he begins a lengthy process of letting go of his expectations and past memories. He stops clinging on what happened then, to what should be, and instead starts to realize he should interact with his environment as it is now. How his relationship with his sister progresses perfectly displays that change within him.
⠀⠀In a certain part of the story, he reminisces about a girl he used to be classmates with during middle school, called Hiiragi. She had pretty much the same mindset as him, and so he considered themselves as "loner buddies". Both of them didn't interact during both middle school and high school, until graduation when they skipped the ceremony and bumped into each other in the school's music classroom. In one of the times when he was stalking Tokiwa, he recognizes her, and finds out she's stalking him as well. This is important later on, since she's drawn to Tokiwa, and MC is drawn to Tsugumi.
⠀⠀Now for the really spoilery part:

Now, I don't want this review to just be a summary of the story with just a bit of my thoughts sprinkled in and there.
⠀⠀The main theme of the story is, from my perspective, the debate of "Nature vs. Nurture". The MC was so fixated on the previous events that remained in his memories—the Nature aspect—, that he failed to take into account that none of the things that were happening, or the people he was surrounded by, which were "the same" from his perspective, were instead fundamentally different due to different factors—the Nurture aspect—.
⠀⠀Just because they were his parents, his sister, or his classmates, that didn't mean that they were going to be the exact same. He assumed it'd be the case, and as such he got fixated to such an unhealthy point, that he didn't consider Honoka as his sister, but his "second sister", same with everyone else. He alienated himself by thinking that every person he met would be the same, so he never took their current personalities and quirks into account when trying to develop relationships. The people he once knew were no more, but he couldn't realize that yet.
⠀⠀As he softened up when it came to the relationship with his sister, he let go of the notion of people's Nature. This is especially important, since at one point he used to think that nobody cared at all about him in the "second attempt", but then that train of thought got interrupted when he considered that his sister actually did. After all, why did she keep going back with him multiple times when running from home? She felt safe around him. This aspect of the book really resonates with me, because even if I don't have a sister, sibling bonds are a crucial part of my own life.

Now, the story does have some weaker aspects to it. Hiiragi, for example, at times doesn't feel like a character with a personality of her own, but rather a plot device to explain the plot twist in the story. Which brings the next point: the plot twist happens too late into the book in my opinion, which makes it feel a little bit rushed, but not to an extent where it becomes detrimental for the whole thing.
⠀⠀These points, however, are forgivable. They only show Miaki's inexperience at the time, and when you compare his following works, you can really notice that he fleshes out his deuteragonists and side characters in a more tasteful manner, as well as the flow of the story being smoother and more cohesive.

All in all, while so far I think this is the worst Miaki Sugaru novel I've read, it's still a beautiful story, and I wish I could write as well as he did at my age (he was also 23 when he published this novel). I am looking forward to reading his next novel in my list, that being 「いたいのいたいの、とんでゆけ」or "Pain Pain, Go Away".
⠀⠀I also urge everyone who enjoys melancholic stories to give him a try. While the official English translations are very limited, there are fan translations out there in the wild. Although I don't think I'd be allowed to elaborate further, since that'd be breaking some guidelines, I do encourage you to purchase the Japanese editions if you have the means and the experience with the language. I personally think a story is best enjoyed in its native language, and his stories are too good for people to miss out on experiencing them.