The high-concept science fiction series Fringe returns for its fourth series on Sky1. Created by JJ Abrams, the man behind Lost, Fringe was an instant success when it was launched to critical acclaim in 2008. After two thrilling series, Fringe has garnered a dedicated fan base following the exploits of the Fringe Division, a group devoted to the study of fringe sciences, investigating extraordinary and seemingly inexplicable occurrences known as'the pattern'. The team is comprised of FBI Agent Olivia Dunham (Anna Torv), eccentric scientist Walter Bishop (John Noble) and his son Peter (Joshua Jackson) as they investigate a series of otherworldly atrocities. Throughout the series, it has become apparent that'the pattern'is a result of Walter's experiments with contacting an alternate version of our world. In series three, we discovered that the terrible atrocities that the team investigate can be traced back to the moment that Walter visited the alternate world and stole their version of Peter after his own son died. Opening up a portal into the other world not only allowed various bizarre mutations to slip through the cracks and cause chaos over here, it infuriated the alternate version of Walter (known as Walternate)– prompting him to declare war on our world. His version of the Fringe Division have been sent undercover over here, including their Olivia (known as Fauxlivia) who fell in love with Peter and became pregnant with his child. At the end of series three, Peter travelled into the future and realisedthe only way to stop Walternate destroying our world was to create a bridge between the alternate universes and for the two to work together. However, bringing about peace, Peter somehow changed history and vanished from Walter and Olivia's lives. The mystery of what Peter did and where he is now will be revealed as the fourth series continues.Fringe returns to Sky 1 for its fourth series on Wednesday, 28 September at 10pm.