Secrets and Regrets (Larry Stylinson AU)

Sixteen years. That is how long Louis has been away, and Harry is heartbroken. More than that, shattered. He can't imagine why his husband would leave him, or what he did wrong. Then, one day, a teenager claiming to be Harry's son shows up on his doorstep, and Harry soon finds out the impossible can happen and wonders that this means for him and Louis. Will Louis ever show his face again, or will Harry only have the stranger who is supposedly his son to hold onto?

1. Prologue