Knox was a former catcher and manager for the Cincinnati Reds who got traded to Anaheim to manage the California Angels who lead them on a horrible losing streak and gets frustrated at them everytime they lose. During a game, Knox gets ejected for attacking his pitcher and at the end of the game, he is interviewed by Angels radio announcer Ranch Wilder another former player who turns out to be Knox's nemesis from their playing days, while they were arguing, Knox punches Wilder for pay back.
Meanwhile, a young foster kid named Roger Bowman prayed for help from real angels to make the team win so he and his father can live together. At the next game, Knox began to see that his team is playing like they've never played before because Roger can see the real angels helping them out and the Angels win for the first time with Knox as their manager and Roger won a chance to get photographed with Knox on the field, Knox refuses to get a photograph with kids because he really hates them, while Roger is getting his photo taken with him, he tells them about the real angels helping out, the next day, Knox questions his team about game they won and they tell him it that it felt like people were grabbing them. Knox delivers the photo to Roger and his friend J.P., he asks them to be regular fans at the home games so Roger can let him know about the real angels and they agree.
As the season goes on, the Angels win more games with the help from the real angels and Knox becomes close friends with Roger & J.P.. The team makes it to the championship, but J.P. shows up at the first championship game alone because Roger had a court hearing about his father giving up custody to him which made Knox unhappy, The Angels lose the first game of the championship, J.P. tells Wilder about the real angels and Wilder attempts to get Angels' owner Hank Murphy to fire Knox.
Knox returns J.P. home at the same time Roger returns home from his court hearing, their caretaker Maggie Nelson tells Knox about Roger's dad abandoning him, then Knox tells Roger that when he was Roger's age, his father barely spent time with him or his brothers, because their father couldn't take of himself which led to Knox being a very frustrated man for all his life. Knox then warns Roger that if he goes through life thinking more people would let him down, Roger will hate children when he becomes an adult and be more frustrated like Knox was prior to meeting him and J.P..
The next day Murphy tells Knox that he needs to relieve him of management because of the real angels helping out. Knox says that they have one game left, then Murphy tells Knox that he already arranged a press conference allowing him to retract this statement. While at the press conference, Roger, J.P. and the entire team stands up for Knox saying they won't play for anyone but him. Murphy, touched by the faith and loyalty decides to keep Knox by the team's request and go for the championship.
At the championship game Al the Boss Angel tells Roger that the angels can't help because of championship rules and later Roger and the entire stadium (except Wilder and their opponents) are doing a wing signal that Knox helped Roger do earlier in the movie. The Angels win the Championship with Murphy firing Wilder for his insults to him, Knox and the players, Knox tells the team that they didn't need the Angels, when Knox returns the boys home, he tells them good news that he called the family court and asked them if he would adopt Roger and J.P. and they agreed.