This review covers both Complete Collection volumes, the completed series 
 Naho Takamiya begins High School with a letter from herself ten years in the future. The letter tells her to watch over the new transfer student, Naruse Kakeru. Naho's future self explains in the letter step by step how she can save him from a devastating future. 
 Time-travel stories aren't really my thing. They usually end up being really confusing and full of plot holes (many authors try to avoid it for a good reason). However, Orange is a time-travel story that is done very, very well. Just to clarify, it's not a story where characters are traveling back and forth through time getting into a lot of mishaps. It's a simple story about changing the course of events to alter the fate of one's future. VERY easy to follow. 
 Kakeru was such an interesting and mysterious character. You wonder why he's so depressed and when you find out, you totally get it. He's such a relatable character. There are often times when I can't relate to what he's going through. It makes me think, "How would I be able to help Kakeru, if I were Naho and her friends?". It's interesting to see what Naho and her friends come up with. 
 Naho's friends made up a lot of the entertainment in this manga. They have colorful personalities, and are very supportive when Naho is struggling to help Kakeru. Hagita is my favorite! Naho herself is adorable and I love her as much as her friends, but her timid personality kind of drove me crazy sometimes. The letter really made this a suspenseful story. There are times when Naho either doesn't listen to the instructions she's supposed to do or completely mess them up. 
 It's not a perfect story, but I don't think it has to be perfect to be incredible. I'm just going to point out some things that make it "not perfect" in a spoiler tag. Only one of the reasons actually bothers me. So if you HAVE NOT read this, DO NOT look at the tag. MAJOR SPOILERS: (view spoiler)[ 
 1. Wouldn't it have made sense for Naho to make Kakeru see professional help instead of relying on her friends and a letter from the future? Well, yeah. But let's be real, that would make this story a lot less enjoyable. 
 2. Letters finding their way through a black hole that's supposedly in the Bermuda Triangle, just by writing their names, date, and addresses on the letter. It's silly logic, even Hagita thought it was silly, but it worked. And how did they send the letters through the black hole/Bermuda Triangle without getting sucked in themselves? Let's face it, there are some things authors just can't figure out themselves. The Bermuda as a black hole was a great concept though. I also want to mention that I loved the idea that the past and the future were two different parallel worlds. 
 3. This is the only one that actually bothers me a bit. The ending was left a bit open ended. Does Naho end up with Kakeru happily ever after now that she saved him? Or was this a part of the future that was unpreventable, and she going to end up with Suwa either way? The Naho from ten year in the future marries Suwa, so I'd like to imagine Naho marries Kakeru in this new future. They are two different parallel worlds so everybody wins, right? (hide spoiler)]