Episode Title:Countdown to Extinction.Episode Description:Starscream plans to destroy Earth to gather energy from the destruction and make Cybertron his. He sets a timer in Dr. Arkeville's lab. Dr. Arkeville tries to save Earth, but only Decepticons can use their computer. Optimus shoots a pebble from Megatron's gun form, making Starscream return to Earth where he is punished by Megatron.