How to write a story like this?

Your plot description is a bit incomplete, if you let me know a little more, I might be able to help you better. Here's what I can say, though: you have to make it really captivating! You can do this by making it very emotional or personal for you or the reader (the way your story sounds, it looks like it should be pretty emotional and target all the people out there who don't express what they really feel, and boy is that a lot of people!) Good luck to you, I hope your story turns out well and that I helped even a little bit. :)