As soon as a learned that MJ Auch's One Plus One Equals Blue explored synesthesia, I just knew I had to read it. Synesthesia is a neurological condition in which one type of stimulation evokes the sensation of another. I've been completely fascinated by this condition for years and was really looking forward to meeting Auch's two main characters, Basil and Tenzie, who have this gift. While I found One Plus One Equals Blue to be an enjoyable middle-grade read, it turned out to be quite different than I was expecting.One Plus One Equals Blue focuses on 12 year old loner Basil. Basil has always associated numbers with colors and doesn't realize that most other people don't do the same until he starts public school (after being home-schooled). Basil doesn't tell anyone about what he calls his “freakisms”, but when the pushy new girl, Tenzie, befriends him, Basil learns that he's not alone; Basil and Tenzie share synesthesia characterizations. When Basil's absent mother shows up after many years away, Basil's life starts to crack and crumble, and when he and Tenzie get swept into his mother's complicated life, they must rely on each other to keep from falling a part.One Plus One Equals Blue ended up being more than I expected. I went into this book expecting a heartwarming, cute middle-grade read, but instead got something a bit heavier and complex. MJ Auch has certainly written a thoughtful and entertaining story about friendship, family, and acceptance, yet it failed to wow and capture me the way I wanted it to.Auch explores some heavy stuff in One Plus One Equals Blue, like bullying, absent parents, neglected children, and hints of mental illness, and while written in a way that is appropriate for its intended audience, I feel like something is missing in this exploration. The story touches upon some truly thought-provoking ideas, but I think they lack a certain depth. But I do really appreciate how real the situations and characters feel; the author creates a great atmosphere of authenticity.Seeing synesthesia from the eyes of two young characters who have it, and have been created by an author who also has the gift, is a cool experience. I found Basil and Tenzie's descriptions and explanation of their condition, how it affects them, and how they deal with it, to be really interesting. Auch does a great job of showing both the positive and negative aspects of this complex condition. However, I do wish the characters' synesthesia actually played a bigger role in the story and was focused on more.Basil and Tenzie are likable, realistic young characters, but not truly memorable. I like them far more as a pair than as individuals and find their friendship endearing. At times I found it hard to connect with these two, but I was emotionally invested in their story. I don't really care for any of the grown-up characters, which is a bummer.The story itself took some unexpected and interesting and maybe a few unnecessary turns, but the ending is satisfying.MY FINAL THOUGHTS: This middle-grade contemporary lacks that super special spark that makes me LOVE a MG book, but I did like it. Thoughtfully and authentically created, One Plus One Equals Blue is a mostly enjoyable and good read.