David uses the latest 3D technology to explore a world beyond the confines of our human senses. He begins with the secret world of plant movement and uses sinister carnivorous plants to show just how active plants can be.Bladderwort utricularia is a pond-dweller that is among the fastest known, its traps snapping shut in less than a millisecond.As the seasons change, David demonstrates how plants operate on a different time scale to us; how they modify their lives according to the time of year. We discover insects' hidden links with plants, both as pests and pollinators. UV-sensitive 3D cameras reveal the invisible alter-ego of plants and their flowers' mesmerizing patterns; a parallel-dimension of strange colours and stunning patterns through which plants communicate with them.With the aid of visual effects, David steps among the swirling vortices of plant scent; communication signals with which plants are inextricably plugged in to the natural world. And using a tuning fork, he demonstrates how plants and insects can even communicate with music.As autumn envelopes the Gardens, fungi reveal themselves not as the enemies of plants but their vital allies. In Kew's atmospheric Fungarium, David discovers a specimen that has the power of mind control and another that lives underground where it has grown to be so big it can be counted as the largest single organism on the planet. It is 6 times bigger than Kew Gardens itself.David concludes the film in the Princess of Wales Conservatory, where he meets an old friend, the great Titan arum. At 8ft tall, it is the largest flower in the world and a plant he remembers from a previous filming trip to Sumatra. Using heat sensitive cameras, David reveals the Titan arum's secrets, how it uses a combination of heat and powerful scent to punch a hole in the stratified layers of air in the rainforest, enabling it to broadcast its presence across vast distances.