The story takes place in London in 1862. James (Eddie Redmayne) is a very ambitious young scientist who is committed to studying weather forecasting technology. However, his financial difficulties prevent him from using his hot air balloon to bring his research results to the sky, so he found a woman named Emilia (Felicity Jones). Emilia is a very experienced hot air balloon pilot, but now she is addicted to a painful past. She agreed to James' request, and the two began their adventure together by flying a hot air balloon, and with wisdom and courage, they reached a height that no human has ever set foot on. However, the higher they fly, the greater the danger they face.