Ed Kennedy, a 19-year-old cab driver convinced of his own mediocrity, is caught in a bank robbery. For reasons he does not understand, he grabs the bank robber’s gun and prevents the robber’s escape. The media briefly hails Ed as a hero, but the excitement quickly dies down and Ed returns to his ordinary life of driving a cab, hanging out with his coffee-drinking mutt, and playing cards with his friends, Marv, Ritchie, and Audrey. But one night, Ed receives a mysterious envelope in the mail which contains an Ace of Diamonds with three addresses written on it.
Uncertain of the sender of the card, Ed decides to go to the first address listed on it. At that address, he witnesses a drunk man sexually assaulting his wife. Ed realizes the card wants him to help the wife and her daughter, but he feels unequipped to face the large, abusive man. So, he decides to move on to the next address. At the second house, Ed meets Milla, a lonely elderly woman with Alzheimer’s disease who believes Ed is her late husband. Ed helps her by spending time with her. Then, he progresses to the third address and sees a teenage girl running barefoot in preparation for track meets. He learns her name is Sophie and that she lacks confidence and always loses her races. Ed gives her an empty shoe box and although Sophie still doesn’t win her races, she now has confidence in her abilities. Finally, Ed returns to the first address, but he still does not know how he will stop the abusive man. One day, a gun appears in Ed’s mailbox, so Ed uses it to threaten the man until he promises to never hurt his wife again.
Having helped all the people on the card, Ed returns home to find two masked men waiting for him. The men, who are named Keith and Daryl, beat Ed up and take the gun, before giving Ed a letter and the Ace of Clubs. Afterward, Ed confesses his attraction to Audrey, but she only wants to be his friend. The Ace of Clubs contains a clue which, along with a strange passenger in Ed’s cab, leads Ed to three names written on a stone in the local river. The first name belongs to a selfless priest whom Ed helps boost attendance at his church by throwing a big party. The second name is a single mom who dedicates her life to her children. Ed helps her by buying her an ice cream cone, because he believes she deserves to be taken care of as well. The final name leads Ed to a teenage delinquent named Gavin, who frequently brawls with his older brother, Daniel. Ed beats up Gavin himself because he believes an outside enemy will unite the brothers. After Gavin and Daniel work together to beat up Ed as revenge, Ed knows he has completed the Ace of Clubs.
Ed receives the next card at the local amateur football game. This card, the Ace of Spades, has the names of three authors written on it. Before Ed can look up the names, he tries to kiss Audrey, but she rejects him once again. Ed returns to the card and discovers that each author has a book that corresponds with a street name in his town. On the first street, Ed helps a poor but loving family enjoy a moment of beauty after buying them new Christmas lights to hang up on their house. At the next street name, Ed sees his own mother on a date with a man. Ed confronts his mother, because his dad died only the year before and his mom generally treats Ed with hostility, and his mother reveals that she hates Ed because he is an underachiever like his father. After reconciling with his mother, Ed goes to the third street, which contains an old theater operated by an elderly man named Bernie. Ed decides he can help Bernie by seeing a movie at the theater with Audrey. However, while Ed and Audrey are watching the movie, the screen suddenly plays video of Ed helping the people on the cards. Ed finds the Ace of Hearts left behind in the theater.
The Ace of Hearts has three movie titles written on it, which lead to Ed’s three friends. First, Ed motivates his lazy friend Ritchie to begin looking for a job so that he may find a purpose in life. Then, Ed helps his irritable friend Marv reunite with the girl he has always loved and the child they share. Lastly, Ed slow dances with Audrey, who fears emotional intimacy, to encourage her to allow herself to love him back.
Though Ed excitedly believes he has finished the entire mission of the cards, he receives a Joker with his own address written on it. In disbelief, he goes through the normal routine of his life, until one day a man gets into his cab and instructs Ed to drive to each address listed on the cards so far. Ed realizes the man is the bank robber from the beginning of the story, and then the man directs Ed to go home. Ed enters his house and finds a stranger sitting on his couch. The young man explains that he sent Ed the cards in order to prove that if someone as average as Ed can commit extraordinary acts of kindness for others, then truly anyone can. The man hands Ed a folder detailing every action Ed has taken since the beginning of his plan and then leaves. Ed agonizes over the implications of the man’s influence on his life, until Audrey comes over and she and Ed kiss. Ed realizes the kiss is not written in the folder. Then he realizes the man was not using him to help others, but instead was using Ed as a message to inspire everyone to reach beyond their own expectations of themselves to bring good into the world.
