A tiny 1.6-kilometer island in Japan's Seto Inland Sea went from a fishing village of 900 people to an internet sensation where cats once outnumbered humans by up to 36 to 1. But beneath the viral photos of Aoshima lies a demographic collapse and a prediction that the island will be uninhabited within five years. This episode reveals the human story behind Cat Island.

We trace Aoshima from its 1639 settlement by sixteen families through its 1945 population peak, the collapse of the sardine trade in the 1970s, and the 1979 school closure that signaled its decline. We explain how working cats brought aboard fishing boats to fight rodents were left behind, then multiplied into an apex population sustained entirely by tourists and donations.

• How every square meter of the island once served a vital purpose
• The single-commodity ...