From the back of the book:
An ancient, secret war rages across the galaxy, and Earth has become its latest battleground. Welcome to Mechamorphosis, where you don't just pilot the giant morphing robot - you are the giant morphing robot!
The power-hungry Tyrant mechamorphs have followed their peaceful Exile and Animech cousins to Earth, hoping to enslave humankind and suck the planet's resources dry. Only the valiant Exile rebels and the wise Animech warriors can stop them.
In thed20 mini-RPG, players take on the roles of giant morphing robots, intelligent living machines that can change forms to appear as vehicles, weapons, and even robotic animals. Spy on enemies with your miniaturizing massmorph ability, take on airborne foes in high-speed aerial combat, or send your companion mechamorphs - smaller 'bots that merge with your form - off to do battle for you. You can constantly adapt and upgrade your powers with form feats, but beware... so can your enemies!