Christmas Island is home to 80 million red crabs, join adventurer Ben Cropp as he documents the annual journey of these amazing creatures as they make their way from mountain to ocean to spawn. This incredible natural phenomenon is triggered each November by the start of the annual monsoonal rains. With the male crabs in the lead this huge population embark on a perilous journey from the forest covering the mountain down to the seashore. Many do not make it as they encounter the dangers brought to the island by humans. Motor vehicles cause the death of large numbers of crabs but they also encounter other hazards that severely deplete the numbers of crabs actually reaching the ocean.