With a duty to deliver every last letter before Christmas, the beloved quartet of post office detectives-Oliver (Eric Mabius), Shane (Kristin Booth), Rita (Crystal Lowe) and Norman (Geoff Gustafson)-are working around the clock to redirect Santa's mail just as Oliver runs into his former Sunday school teacher (Marion Ross). When they receive an emotional last-minute plea not meant for Saint Nick, but instead written to God, they must delay their own travel plans to make sure one little girl doesn't lose her Christmas joy-something Oliver and Shane are also struggling to find as they each face painful holiday memories. With a little guidance from a mysterious post office volunteer, Jordan (Rob Estes), the Postables are more surprised than anyone to discover they've been a part of more than one miracle on this Christmas Eve.