In this thrilling 48-page junior chapterbook, the menacing COBRA forces have caused a giant asteroid to hurtle toward Earth--and it's up to the G.I. JOE team to stop it! Heavy Duty, G.I. JOE's weapons expert, has never had a challenge like this! How can he protect the Earth from a giant asteroid that COBRA has pulled onto a collision course? If that asteroid hits the ocean, it will cause a tsunami that could flood the entire Eastern seaboard! But leave it to Heavy Duty and the rest of the G.I. JOE team to find a way to keep the Earth safe!