Mike is giving Louis one of his kidneys in the hope that he can lead a fuller life.
Our cameras have been given the rare chance to film the transplant operation - and to follow the journeys of Mike, from Kent, and Louis, from Hampshire. Here's the first of three special reports, from Martin Dowse.
Here is the second of our special reports, from Martin Dowse.
The third and final piece in the series will be on Meridian Tonight at 6pm. Don't miss it.