Speed is on the track, practicing for the Danger Pass Race when a mysterious and fast car comes speeding up behind him. Speed narrowly avoids crashing.
Later, the car drives up behind a man. It flashes X3 on its hood before forcing him off the road. The next day, Speed and a race official talk about the crash and the mysterious car. The official claims not to know anything even after Inspector Detector shows him a clue they found at the crash site, a card that says X3. He later calls a friend, another racing official and warns him about the accident. This guy refuses to stay home every night and becomes the second victim of the mysterious car.
The next day, Trixie prepares a picnic lunch for them but the Inspector asks for Speed's help in catching the fast mystery car. Trixie isn't too happy when Speed agrees. The radio soon reports the car being spotted so Speed and the police go in pursuit.
Speed loses the car but catches up to it later. To his surprise, he discovers the car was driven by remote control with a robot behind the wheel. They manage to find out the robot said "Melange" before shutting down. Pops recalls a race from 15 years ago where a driver named Flash Marker went off the road and died.
Speed, Trixie and Inspector Detector visit the kids of Flash Marker. Flash Jr. is apparently sick and hasn't left the house in a while. When they leave, Flash shows his sister, Lily his secret garage he built under their home. He forces her to sit in the car as he controls it by remote in order to enter the race so they can get revenge.