When an asteroid crashes into Planet Earth, Colin, Sam, Ralph and Peter find themselves trapped in virtual reality collecting souvenirs for the mysterious Agent Berengeur.
They battle with the Stymphalian Birds in Ancient Greece, travel to Aztec Central America, fight with gladiators in the future, awaken the Terra Cotta Army in Ancient China and recieve an icy reception from the Frost Giants.
And then back in London they are given the chance to stop the asteroid and return to absolute reality.