On Halloween night all the angels have their hands full, and this night is no different for Monica, Tess, and Andrew, who attend to a spiritual battle at Salt Lake City's Mercy Hospital. The ambulance brings Lonnie, a deranged and suicidal homeless man. Lonnie frequently visits the ER and Duncan, the head of the ER and Lonnie's best friend from childhood, has diagnosed him with Multiple Personality Disorder. Andrew arrives to comfort Lonnie, but suddenly lucid, Lonnie claims to be ""Gregory"" and recognizes Andrew as an angel! Andrew looks to Tess for some insight and she relates Lonnie's history. Many years ago, when Tess was Lonnie and Duncan's Sunday School Teacher, she taught them that faith in God is like a mustard seed, though little, it can grow to be very large. Despite an abusive home life, Lonnie struggled to have faith, and cherished the mustard seed that Tess gave him. One Halloween though, a prank gone awry resulted in Lonnie burning a house down. Monica then continu