Theo and Leon Smith are flying to Athens with their parents to attend the Olympic Games when, passing Mount Olympus, the aeroplane is intercepted and embroiled in an ancient Greek battle that has raged for thousands of years. Forced to land, the captain is confronted with a conundrum in the clouds that could only have been created by some immortal force. Theo and Leon, fascinated by ancient Greece, are willing participants in the awesome but scary events that follow. Numerous criminals and a net full of birds imprisoned in the clouds by the gods are the source of the terror. Rescued and returned to Athens, the task of helping them to acclimatize to the twenty-first century falls to the Smith family and various academics. While visiting the ruins of Olympia with their ancient friends, the boys find themselves in Ancient Olympia with the race about to start. The all-important victor's speech is interrupted by the unceremonious arrival of Theo's teacher, instigating a series of perilous recriminations. Their lives are endangered many times as they become involved in the bloody battles and rituals of ancient Greece. Tragedy and redemption do not strike, however, until Theo and Leon return to Athens, AD 2004, in time for the Olympic Games.