Deep in the forest lives Millie, a friendly, fearless young girl and her best friend Lou, a clever cautious little cat. Millie and Lou share the forest with exciting creatures, the Forest Folk, all based on mythical folklore. Together, these BFFs are on a magical mission to meet every single one.

Cherie, a Filipino maid, goes to a wealthy family's reception to do some extra work. But when she arrives, she discovers that her job is to look after the dogs. She then meets Milo, the family's young son.

The film is set in a speculative Philippines where air pollution has reached irreparable proportions. Air pollution has rendered breathable oxygen scare. This makes it the main resource around which society revolves. The film follows two protagonists: Leo Sagaysay, a young father and husband who works at the Oxygen Factory, and his wife Rubi Sagaysay. Together they have a son, whom they struggle to support. The appearance of ex-factory worker Tess at their door sets off a chain of events that leads to the downfall of the Sagaysay family.