The Autobots continue to work for NEST, now no longer in secret. But after discovering a strange artifact during a mission in Chernobyl, it becomes apparent to Optimus Prime that the United States government has been less than forthright with them.

Young teenager, Sam Witwicky becomes involved in the ancient struggle between two extraterrestrial factions of transforming robots – the heroic Autobots and the evil Decepticons. Sam holds the clue to unimaginable power and the Decepticons will stop at nothing to retrieve it.

While traveling on vacation through the country of Northeastern of Brazil by bus, the American Alex Trubituan, his sister Bea Tribituan and their friend Amy Harrington meet the also foreigners Pru Stagler, Finn Davies and Liam Kuller after an accident with their bus. They follow a track through the woods and find a hidden paradisiacal beach. They decide to stay in the place drinking beer and dancing funk and parting with the locals and they meet the amicable Brazilian teenager Kiko. They are drugged with “Boa Noite, Cinderela” (Ruffies, literal translation: “Good Night, Cinderella” – a trick used by smalltime crooks to steal naive people) and when they wake up, they are practically naked, with all their belongings, clothes, money, jewels, passports, backpacks etc. stolen. They walk to a small village trying to find a police station, they get into trouble with the dwellers and they are helped by their acquaintance Kiko, who leads them to his uncle’s isolated well-equipped cabin in the …

Autobots and Decepticons are at war, with humans on the sidelines. Optimus Prime is gone. The key to saving our future lies buried in the secrets of the past, in the hidden history of Transformers on Earth.