If one can get over the initial misconceptions of this being a pedophile manga and whatnot (due to the misleading title) what follows is an absolute gut-wrenching story that focuses on the importance of life and time.
The artstyle leaves a bit to be desired but that isn't the main focus of this manga.
Would recommend everyone to read it at least once, especially if one is/has been dealing with issues of grief, doubt and loss.