Calum, Michael, Luke and Ashton had moved back to Australia once they had finished with school, college and university. The group of boys become a worldwide famous band called Five Seconds of Summer, but give it all up when they all have children of their own, forgetting about the fact that they were friends. But what happens when old events come back to haunt them? The new Plastics take on board as their mission to destroy Calum's son, but what happens when Thomas realises that the Plastics are Michael, Ashton and Luke's children? Will Thomas befriend the Plastics? Will someone try to save him? Will the Plastics end or become stronger?