British ex-pats and best mates Steve and Brad now live in different parts of Australia with their wives and families. Every year, the two families reunite for a summer holiday and this year, Steve, Sarah and teenagers Mia and Tom are visiting Brad, Louise and son Kip at their new home in the remote Victorian bush. While the reunion is a warm one, various tensions bubble beneath the surface. Upon seeing the palatial property, Steve feels insecure. Tom is nursing an injury and Kip doesn't believe his explanation for how it happened. Louise also senses Sarah is not herself. She's right… behind closed doors, Mia reveals her belief that Steve is having an affair, and Sarah is too weak to confront him. The families venture to the nearby river for a picnic, in celebration of Steve and Brad's birthdays. As the mercury rises, Brad recounts the story of how he and Steve first met in their native UK. Later, Steve breaks down and tells Brad the true nature of his duplicitous behaviour. However, Steve's happiness is shattered when Mia's estranged boyfriend, Jet, arrives. Ever the nice guy, Brad invites Jet to at least stay the night. Steve isn't happy, though Mia is grateful. The next morning, Jet decides to drive back to Sydney, leaving the families in peace. However, Sarah is anything but relaxed, wracked with guilt, she is the one with the secret. Jet makes a surprise return. The road is closed due to bushfires. While they aren't in any immediate danger, nobody is able to leave, whether they want to or not.

The truth behind Tom's injury is revealed, and Brad's hopes with Mia are explored. Kip confesses to Tom he is growing marijuana in the shed. Though Sarah struggles with the harsh realities of separation, she commits to a future with Brad. At rock bottom, Steve notices smoke on the horizon, concerned they really are in danger despite Brad insisting they aren't. Louise's panic rises when a nearby town is evacuated. Sarah, too, starts to feel overwhelmed by everything. Distressed by his mother's betrayal, Tom tells Kip he wants to get stoned. Seeing Brad, Tom panics, runs into the smoky bush with Brad pursuing him to a steep ledge. The teenager vanishes – did he fall?