Things have been rough lately for the Doherty family. Not long after the sudden and unexpected passing of her husband, Maddy (ROBYN LIVELY) must now contend with the fact that her 8-year-old son, Tyler (TANNER MAGUIRE), has a rare form of brain cancer. With her mom, Olivia (MAREE CHEATHAM), now present to help out at home, Maddy is going to return to work, but Tyler's teenage brother, Ben (MICHAEL BOLTEN), is having issues with all of the bad things that have happened to his family of recent.
Also facing a hard time, albeit of a different sort, is Brady McDaniels (JEFFREY S.S. JOHNSON). He's a postal worker whose wife left him and took their young son following Brady's DUI arrest, yet the troubled man continues to drink. He also has a sour work ethic, meaning he isn't happy when he's assigned to take over the foot delivery route for another mailman who's going on an extended leave.
Brady's new post not only puts him in contact with the cantankerous Cornelius Perryfield (RALPH WAITE) who expects his mail on time every day, but also Tyler who's been sending letters addressed to God. Brady doesn't know what to do with them, but his boss says he should figure it out himself, while the local pastor tells Brady that God choose him to handle those letters. Accordingly, Brady starts to get to know and like the boy and his best friend, Sam (BAILEE MADISON), Cornelius' spunky granddaughter.
She's quite protective of Tyler, and thus doesn't take kindly to other students, such as Alex (C.J. AMARI), who make fun of Tyler when he returns to school following a break in his cancer treatment. With everyone wondering why God is making Tyler go through all of this, the boy learns that he's God's warrior, chosen to make sure everyone sees the light, with his letter writing campaign soon getting others to follow suit.