Inner city kids from a poor neighborhood go up against the undefeated Beverly Hills Junior National Karate Team.

Alexander's day begins with gum stuck in his hair, followed by more calamities. Though he finds little sympathy from his family and begins to wonder if bad things only happen to him, his mom, dad, brother, and sister all find themselves living through their own terrible, horrible, no good, very bad day.

A man who stops into a foster home to drop off some donations soon tells the kids a story about two teenage friends who uncover a long-lost medallion that transports them back in time.