Those robots in disguise are back on the big screen this summer in Transformers: Revenge of the Fallen. Transformers were popular toys in the 80s, and the shape-shifting automatons starred in a popular cartoon. The massive machines were resurrected two years ago in Michael Bay's Transformers, bringing the beloved franchise to a new generation of movie-goers, and causing mass nostalgia for 20-somethings around the world. To recap: at the end of the first instalment, human hero Sam Witwicky (Shia LeBeouf) helps the good Transformers, the Autobots, defeat the Decepticons and destroy the All Spark, the substance which brings mechanical objects to life. A tiny amount remains, but not enough to return the good guys to their home planet Cybertron. In Transformers 2, set two years later, Sam is on the brink of adulthood, setting off for college, leaving his parents and guardian robot Bumblebee behind, and vowing to stay faithful to his girlfriend Mikaela (Megan Fox). The Autobots, who know all about leaving home, have been living alongside humans and working closely with the military as part of a top-secret team called Nest. Teaming up with field commanders Major Lennox (Josh Duhamel) and USAF Master Sergeant Epps (Tyrese Gibson), the Nest team is on a mission to hunt down whatever Decepticons remain on Earth. The Decepticons, of course, have plans of their own for the not-so-bright future of the human race. This film introduces new characters on both sides of the robot war. The Autobots introduce The Twins, Mudflap and Skids, a pair of Chevrolet-shaped robots that can combine to form an ice cream van, and Arcee, a female Transformer who takes the form of a motorbike. On the dark side, new Decepticons include Devastator, a mega-transformer made up of several individuals, and Soundwave, which can transform into a satellite to steal classified information. Finally, there's chief villain, The Fallen. Megatron's mentor came to Earth thousands of years earlier, and has been waiting to destroy the Sun and use its energy to create Energon, a source of power which can only be created when a star is destroyed. As Sam adjusts to his new life, he learns the truth about the Transformers' origins, knowledge which puts him at the mercy of the Decepticons. Directed again by Bay, Transformers 2 is one of the most eagerly awaited films of the year. Unusually, it will be released in Hong Kong and the US on the same date, so head to the cinema from Wednesday.