Hollywood's hottest canine commodity has gotten hopelessly lost after wandering away from his master, and now the former movie star has become the beacon of hope for a small-town firehouse on the verge of collapse. Rex is the dog that every child in America has fallen in love with. A pompous A-list barker whose list of perks overshadows that of even the most esteemed Hollywood actor, Rex 's fate takes an unexpected turn when a skydiving stunt goes awry and his handlers assume that their cash-canine has perished as a result. Now, despite being very much alive, the former doggie diva has become just another mangy stray wandering the streets in search of a home. Lost in an unfamiliar city and pursued by animal control, Rex seeks refuge in a run down building that soon goes up in flames. Shane Fahey (Josh Hutcherson) is a rebellious preteen whose single-parent father, Connor (Bruce Greenwood), is struggling to care for his son and cope with the death of his brother, the former captain of the local fire department. Pressed with the responsibility of getting the crumbling inner-city fire house back in working order while helping his 12-year-old son deal with the untimely loss of a beloved family member, Connor just can't seem to convince Shane to keep his grades up and stop ditching school. Upon rescuing the unidentified Rex from the four-alarm blaze, Connor attempts to teach young Shane the meaning of responsibility by charging him with the task of locating the dog's owner. Despite an initial clash of personalities, the headstrong mutt and the disobedient adolescent soon form a strong bond. Subsequently adopted as the scrappy fire department's new mascot, Rex proves just the catalyst needed to reenergize the dejected firefighters and reform the once-tenuous bond between father and son.