The world's nuclear powers are in a race to build the Phi bomb, an apocalyptic weapon that can destroy the earth, Tambi is determined to stop them but she'll have to act fast—the prototype will be ready in five years. When her team in Russia meets with disaster, Tambi turns to Katchoo with a dire call to arms that requires the ultimate sacrifice. All of Terry Moore's series unite as one epic saga in Five Years. At the center of it all is Katchoo, the haunted woman with a wild past who would do anything for Francine including leave their island paradise to stop the creation of a doomsday device hailed as The Last Bomb.

The Phi bomb is under construction in Russia and Katchoo is determined to stop it. Her diplomatic trip to Moscow is sabotaged by a dangerous KGB assassin and Zoe must complete the mission and find the man developing "the last bomb." Meanwhile, Stephanie retrieves one half of the Cleopatra scroll that started the new arms race and quickly discovers the author wants it back! The stakes have never been higher as Katchoo and friends try to leave Russia with one of the country's top physicists and bring a dangerous nuclear game to a stalemate!