This is a well-developed, effective story @rishagamo. I'd like to offer a tip about making the writing clearer for the reader: quotation marks.

At some points in the story it is hard to follow whether you are referring to Mark or Mathew. If quotation marks were used in dialogue that would be a good cue for the reader.

You do have an excellent story arc, and that is really what a story hangs on. :)