In the first book of the series, THEY, Jess and Jace Grisham survived a harrowing adventure to find their father and expose the truth that aliens have been visiting Earth for years. In Us, "They" have arrived and nothing will ever be the same. The battle for the future of the planet is just beginning. The Erdeans, a race of highly-advanced locust-like creatures, are arriving in force to strip our world of the rarest natural resource in the galaxy. The only hope is to stop them before their full alien army can arrive. The Erdeans, though, have infiltrated all levels of our government. Jess and Jace must fi-gure out who they can trust if they hope to fulfill the prophecy naming them as the saviors of life in the universe.

They're not alone. The Origin Society is a secret group here on Earth that has been preparing for this invasion for centuries. One of the members, Max, has helped the twins out of several jams, but can he be trusted or has he, too, been compromised?