Frank and Joe travel to Philadelphia where they intend to prevent an attack on an extreme sports contest called the Big Air Games.

Terror at 12,000 feet -- Duck! -- Extreme danger -- Warning signs -- Killer wheels -- Attacked! -- Blood on the half pipe -- Dead on arrival -- Who is Mr. X? -- Let the games begin -- Crash and burn! -- The biker in black -- "Meet me at midnight" -- A real shocker -- Heroes.